Made some very minor changes to avoid import aliases.

This is the convention that I followed to export objects in the
`src/sidebar/store/modules`:  name of the file plus the word `Module`. For example, `direct-linked.js` exports `directLinkedModule`.

The unused type referred to a class that has been deleted.

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

The functionality to compute the buckets has been split in two steps:

1. Guest frame computes and sends a list of the anchors's top/bottom
   positions with the `anchorsChanged` RPC event.

2. In the host frame, `BucketBar` uses the list anchor's positions to
   compute the buckets.

There is one issue with the current approach: if an iframe doesn't cover
the entire host frame's viewport buckets can appear offset.

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.1062.0 to 2.1066.0.
- [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/v2.1062.0...v2.1066.0)

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Bumps [@sentry/cli](https://github.com/getsentry/sentry-cli) from 1.72.0 to 1.72.1.
- [Release notes](https://github.com/getsentry/sentry-cli/releases)
- [Changelog](https://github.com/getsentry/sentry-cli/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-cli/compare/1.72.0...1.72.1)

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Bumps [sinon](https://github.com/sinonjs/sinon) from 12.0.1 to 13.0.0.
- [Release notes](https://github.com/sinonjs/sinon/releases)
- [Changelog](https://github.com/sinonjs/sinon/blob/master/docs/changelog.md)
- [Commits](https://github.com/sinonjs/sinon/compare/v12.0.1...v13.0.0)

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Bumps [rollup](https://github.com/rollup/rollup) from 2.66.0 to 2.66.1.
- [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/v2.66.0...v2.66.1)

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Bumps [karma](https://github.com/karma-runner/karma) from 6.3.11 to 6.3.12.
- [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/v6.3.11...v6.3.12)

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Bumps [commander](https://github.com/tj/commander.js) from 8.3.0 to 9.0.0.
- [Release notes](https://github.com/tj/commander.js/releases)
- [Changelog](https://github.com/tj/commander.js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tj/commander.js/compare/v8.3.0...v9.0.0)

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Bumps [preact](https://github.com/preactjs/preact) from 10.6.4 to 10.6.5.
- [Release notes](https://github.com/preactjs/preact/releases)
- [Commits](https://github.com/preactjs/preact/compare/10.6.4...10.6.5)

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Rename the module to match the `src/shared/messaging` directory name.
We've considered moving the integration test under
`src/shared/messaging/test` but have punted on that for now.

Make it easier for future developers to understand the inter-frame communication
code by grouping it in a directory with a short README and an index module that
defines the API for use by other parts of the client.

Bumps [tailwindcss](https://github.com/tailwindlabs/tailwindcss) from 3.0.15 to 3.0.18.
- [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/v3.0.15...v3.0.18)

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Bumps [@sentry/browser](https://github.com/getsentry/sentry-javascript) from 6.17.0 to 6.17.3.
- [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/6.17.0...6.17.3)

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  dependency-type: direct:development
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Bumps [puppeteer](https://github.com/puppeteer/puppeteer) from 13.1.1 to 13.1.3.
- [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/v13.1.1...v13.1.3)

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Bumps [chai](https://github.com/chaijs/chai) from 4.3.4 to 4.3.6.
- [Release notes](https://github.com/chaijs/chai/releases)
- [Changelog](https://github.com/chaijs/chai/blob/4.x.x/History.md)
- [Commits](https://github.com/chaijs/chai/compare/v4.3.4...v4.3.6)

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Bumps [eslint](https://github.com/eslint/eslint) from 8.7.0 to 8.8.0.
- [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/v8.7.0...v8.8.0)

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Bumps [dompurify](https://github.com/cure53/DOMPurify) from 2.3.4 to 2.3.5.
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](https://github.com/cure53/DOMPurify/compare/2.3.4...2.3.5)

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Replace use of local utility classes with tailwind
utility classes that do the same thing. Structure the utilities
layer for both sidebar and annotator.

Clarify what happens if we try to test whether a VitalSource frame
contains "real content", before it has finished loading.

The real VitalSource viewer loads the final URL with a form submission,
which does not update the `src` attribute of the iframe. Make the demo
page also load the app in a way that doesn't modify the parent frame's
DOM, to ensure the client is not relying on that.

I don't know if these scenarios can actually happen in the real VS viewer, but
this feels like appropriate defensive coding.

Navigations between sections of a book in VitalSource happen in several
steps:

 1. The iframe for the previous chapter is removed
 2. An iframe is created for the new chapter. The initial load of this
    iframe contains a "blank" page with the chapter content in an
    encoded/encrypted form as hidden text in the page.
 3. The chapter content data is submitted to the VS backend via a form
    POST request, which returns the decoded content

Previously the Hypothesis client would sometimes detect the new iframe
after step 2 and inject the client before step 3 had completed. As a
result the client would be injected into the blank frame, then
immediately unloaded, and not re-loaded into the "real" content frame.

Make injection more reliable by:

 1. Checking whether the content frame is a "blank" frame or not before
    injecting the client.
 2. Listening for `load` events on the frame and re-injecting the client
    if the iframe is navigated

The VitalSource EPUB test page was missing an important behavior of the
real VS viewer, where the content loads in multiple steps - see code
comments for details. The client does not load reliably into the new
chapter after a navigation due to this behavior of the VS viewer.

Get the WebSocket URL from the /api/links endpoint instead of the `websocketUrl`
configuration in app.html. This ensures that the client uses the correct
WebSocket endpoint for the h API service it is currently talking to, which may
be different than the default when  `services` configuration is specified.

When updating the tests, several had to be reworked to be less sensitive
to the number of microtask ticks in between certain events.

This depends on the h change in https://github.com/hypothesis/h/pull/7253.