When computing the amount of free space between the right edge of the
main content and the edge of the sidebar, allow for the padding
allocated between the sidebar and the content. This fixes an issue where
the main content would touch the sidebar exactly instead of having a
margin between it and the content.

Also tweak the padding value slightly to be a multiple of the 4px grid
cell size used in the design system.

Add calls to `act` around proxy method calls that trigger store changes
which in turn schedule deferred updates within Preact components. This
should hopefully fix an issue with flakey tests due to updates being
flushed after the tests have finished executing.

This makes the VS EPUB test page more accurately reflect the real VitalSource
viewer. More importantly, it also triggers the heuristic that the Guest class
uses to decide whether to enable side-by-side mode for an iframed guest.

To make side-by-side mode work for VitalSource EPUB books, the guest in
the VS content iframe needs to invoke the integration's `fitSideBySide`
method. This is done in a generic way by making guests in iframes call
this method, but only if they know that the iframe fills the host frame.

In the VitalSource integration, enable the side-by-side mode in the
underlying HTML document integration.

Implement side-by-side mode for HTML documents, disabled by default by a
a `HTMLIntegration.sideBySideEnabled` feature flag.

For ease of testing, some helpers have been split into a separate
html-side-by-side.js module.

Rename these types:

* `MergedConfig` -> `SidebarSettings`
* `HostConfig` -> `ConfigFromHost`
* `SidebarConfig` -> `ConfigFromSidebar`

Also, update type usage to favor `SidebarSettings` in services and
components.

Remove support for retrieving host configuration from an unspecified
ancestor frame. This was used by the legacy LMS application and is no
longer needed.

Add a command which runs TypeScript against a subset of the codebase, currently
just src/shared/, with the `noImplicitAny` option enabled.

This will allow us to gradually work towards the goal of having the entire
client codebase typecheck with this option enabled. Once this state is reached
the `noImplicitAny` option can be enabled in the main TS config file
(src/tsconfig.json) and the `yarn typecheck-no-any` command and associated TS
config file can be removed.

Fix various errors and omissions found when TypeScript's `noImplicitAny`
option is enabled.

Bumps [showdown](https://github.com/showdownjs/showdown) from 1.9.1 to 2.0.0.
- [Release notes](https://github.com/showdownjs/showdown/releases)
- [Changelog](https://github.com/showdownjs/showdown/blob/2.0.0/CHANGELOG.md)
- [Commits](https://github.com/showdownjs/showdown/compare/1.9.1...2.0.0)

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Bumps [@babel/core](https://github.com/babel/babel/tree/HEAD/packages/babel-core) from 7.17.2 to 7.17.5.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/main/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/commits/v7.17.5/packages/babel-core)

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Bumps [sass](https://github.com/sass/dart-sass) from 1.49.7 to 1.49.8.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sass/dart-sass/compare/1.49.7...1.49.8)

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Bumps [preact](https://github.com/preactjs/preact) from 10.6.5 to 10.6.6.
- [Release notes](https://github.com/preactjs/preact/releases)
- [Commits](https://github.com/preactjs/preact/compare/10.6.5...10.6.6)

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Bumps [@sentry/browser](https://github.com/getsentry/sentry-javascript) from 6.17.7 to 6.17.9.
- [Release notes](https://github.com/getsentry/sentry-javascript/releases)
- [Changelog](https://github.com/getsentry/sentry-javascript/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-javascript/compare/6.17.7...6.17.9)

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Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss) from 3.0.22 to 3.0.23.
- [Release notes](https://github.com/tailwindlabs/tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/tailwindcss/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/tailwindcss/compare/v3.0.22...v3.0.23)

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Bumps [dompurify](https://github.com/cure53/DOMPurify) from 2.3.5 to 2.3.6.
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](https://github.com/cure53/DOMPurify/compare/2.3.5...2.3.6)

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Bumps [express](https://github.com/expressjs/express) from 4.17.2 to 4.17.3.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](https://github.com/expressjs/express/compare/4.17.2...4.17.3)

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Bumps [puppeteer](https://github.com/puppeteer/puppeteer) from 13.3.1 to 13.3.2.
- [Release notes](https://github.com/puppeteer/puppeteer/releases)
- [Changelog](https://github.com/puppeteer/puppeteer/blob/main/CHANGELOG.md)
- [Commits](https://github.com/puppeteer/puppeteer/compare/v13.3.1...v13.3.2)

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Bumps [mocha](https://github.com/mochajs/mocha) from 9.2.0 to 9.2.1.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v9.2.0...v9.2.1)

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Bumps [core-js](https://github.com/zloirock/core-js) from 3.21.0 to 3.21.1.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/zloirock/core-js/compare/v3.21.0...v3.21.1)

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Bumps [rollup](https://github.com/rollup/rollup) from 2.67.2 to 2.67.3.
- [Release notes](https://github.com/rollup/rollup/releases)
- [Changelog](https://github.com/rollup/rollup/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rollup/rollup/compare/v2.67.2...v2.67.3)

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Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.1073.0 to 2.1077.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.1073.0...v2.1077.0)

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Previously the following attributes in the meta tag:

```
<meta name="DC_IDENTIFIER" .../>
<meta name="EPRINTS.TITLE_" .../>
<meta property="OG:URL" .../>
<meta name="CITATION_DOI" .../>
<meta name="PRISM_TITLE" .../>
<meta name="TWITTER:SITE" .../>
```

produced a metadata dictionary like this:

```
{
  dc: {IDENTIFIER: [...] },
  eprints: {TITLE: [...]},
  facebook: {URL: [...]},
  highwire: {DOI: [...]},
  twitter: {SITE: [...]}
}
```

Now, with the modifications introduced in this PR, it produces a
metadata dictionary where all the keys are lowercase:
```
{
  dc: {identifier: [...] },
  eprints: {title: [...]},
  facebook: {url: [...]},
  highwire: {doi: [...]},
  twitter: {site: [...]}
}
```

I have confirmed that `h` expects the lowercase version of the keys
`identifier` and `doi`:

https://github.com/hypothesis/h/blob/73dacc722367c44903ff3c6f610712ba8f43934d/h/util/document_claims.py#L222

https://github.com/hypothesis/h/blob/73dacc722367c44903ff3c6f610712ba8f43934d/h/util/document_claims.py#L247

Hence, if they are not provided as lowercase version, they will be
ignored and the document equivalence will not work.

Notify newly connected guest frames of the current sidebar layout. This
allows newly created guests to properly activate side-by-side mode if the
sidebar is already open and the guest supports it. This is relevant when
navigating between chapters in a VitalSource book.

Only load the `pdfjs-overrides.css` bundle when the client is loaded in
PDF.js.

This fixes an issue where a global styling change that was recently
added specifically for PDF.js [1] ended up affecting other web pages
[2].

[1] https://github.com/hypothesis/client/pull/4208
[2] https://github.com/hypothesis/product-backlog/issues/1270#issuecomment-1039647361

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.1069.0 to 2.1073.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.1069.0...v2.1073.0)

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Bumps [@babel/core](https://github.com/babel/babel/tree/HEAD/packages/babel-core) from 7.17.0 to 7.17.2.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/main/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/commits/v7.17.2/packages/babel-core)

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Co-authored-by: Robert Knight <robertknight@gmail.com>

Before this PR, when there was two frames, A and B, if the adder was in
frame A, it was necessary to __double click__ on frame B to remove the
adder and the selection from frame A.

After this PR, __a single click__  on frame B removes the adder and text
selection from frame A. This behaviour is similar to what happens on a
single frame scenario, where a single click removes the adder and the
selection.

Bumps [follow-redirects](https://github.com/follow-redirects/follow-redirects) from 1.14.7 to 1.14.8.
- [Release notes](https://github.com/follow-redirects/follow-redirects/releases)
- [Commits](https://github.com/follow-redirects/follow-redirects/compare/v1.14.7...v1.14.8)

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Tests sometimes failed because a PortRPC method handler was not called
after the fixed message delivery delay that the tests allowed.

I have not been able to reproduce locally, but attempt to resolve the
issue by waiting for a specific message to be delivered to the
MessagePort instead of waiting a fixed amount of time.

For some test cases which assert that a message was *not* delivered, a
fixed delay is still used. This is acceptable because the test will
still pass in the rare cases where the fixed delay is too short.

In #4195, we removed `clearSelectionExceptIn` RPC event. Instead, the
host frame sends `clearSelection` RPC events to specific guest frames.

The `hasHypothesis` function always returned false because it relied on a global
variable that no longer exists. The fact that it was broken didn't cause
noticeable problems because the client's boot script also has a check for
whether Hypothesis is already injected.

Replace the broken check with a working one that corresponds to the nearby
`injectHypothesis` function.

Bumps [eslint](https://github.com/eslint/eslint) from 8.8.0 to 8.9.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v8.8.0...v8.9.0)

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Bumps [karma](https://github.com/karma-runner/karma) from 6.3.15 to 6.3.16.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](https://github.com/karma-runner/karma/compare/v6.3.15...v6.3.16)

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Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss) from 3.0.18 to 3.0.22.
- [Release notes](https://github.com/tailwindlabs/tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/tailwindcss/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/tailwindcss/compare/v3.0.18...v3.0.22)

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Bumps [@rollup/plugin-replace](https://github.com/rollup/plugins/tree/HEAD/packages/replace) from 3.0.1 to 3.1.0.
- [Release notes](https://github.com/rollup/plugins/releases)
- [Changelog](https://github.com/rollup/plugins/blob/master/packages/replace/CHANGELOG.md)
- [Commits](https://github.com/rollup/plugins/commits/yaml-v3.1.0/packages/replace)

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Bumps [@sentry/browser](https://github.com/getsentry/sentry-javascript) from 6.17.4 to 6.17.7.
- [Release notes](https://github.com/getsentry/sentry-javascript/releases)
- [Changelog](https://github.com/getsentry/sentry-javascript/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-javascript/compare/6.17.4...6.17.7)

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