Fix visibility of submenu item focus rings

Increase highlight opacity

Item submenus inside the `Menu` component are wrappd in a `Slider` to
enable an animated expand/collapse of the submenu. The `Slider` used
`overflow: hidden` to hide any content while collapsed or transitioning.
However this had the unintended effect of clipping focus rings which
extended beyond the bounds of the content.

Fix the issue by changing the `overflow` property to `visible` once the
slider's content is fully visible.

Add assert.rejects()

Replace assertPromiseIsRejected and toResult with assert.rejects
Signed-off-by: Kyle Keating <kkeating@hypothes.is>

- This is used to patch in helper methods into the global assert object such as `rejects()` for testing.
- The new rejects method gives tests the ability to easily test error results in async methods that return a promise.
- Replace all async try/catch tests with assert.rejects
Signed-off-by: Kyle Keating <kkeating@hypothes.is>

Increase the opacity of highlights from 30% to 40% to improve the
visibility of highlights, especially on very light/white backgrounds. Following
https://github.com/hypothesis/client/pull/2017, we can do this without reducing
contrast of highlighted text in PDFs.

Only the color of "first level" (non-nested) highlights was increased,
as nested highlights already had the higher level of contrast.

Improve readability of PDF highlights

These highlights are used to enable various Hypothesis UI interactions
for annotated content on PDF pages which are not yet rendered. They
should be visually hidden however. The highlight in the text layer is hidden
by the `annotator-placeholder` CSS class. We also need to avoid creating
an SVG highlight.

Bump karma from 4.4.1 to 5.0.1

Bump core-js from 3.6.4 to 3.6.5

Bump autoprefixer from 9.7.5 to 9.7.6

Bump escape-string-regexp from 1.0.5 to 3.0.0

Bump sinon from 9.0.1 to 9.0.2

Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 9.7.5 to 9.7.6.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/master/CHANGELOG.md)
- [Commits](https://github.com/postcss/autoprefixer/compare/9.7.5...9.7.6)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 17.1.4 to 17.2.1.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v17.1.4...v17.2.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.653.0 to 2.656.0.
- [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/v2.653.0...v2.656.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [jquery](https://github.com/jquery/jquery) from 3.4.1 to 3.5.0.
- [Release notes](https://github.com/jquery/jquery/releases)
- [Commits](https://github.com/jquery/jquery/compare/3.4.1...3.5.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [core-js](https://github.com/zloirock/core-js) from 3.6.4 to 3.6.5.
- [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/v3.6.4...v3.6.5)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.9.0 to 7.9.5.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.9.0...v7.9.5)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bump terser from 4.6.10 to 4.6.11

Clear selection when changing user

Fix single annotation page

4d210869 removed registration of the
`api` service from Angular, but the component for the single annotation
page still needs it.

Bumps [sinon](https://github.com/sinonjs/sinon) from 9.0.1 to 9.0.2.
- [Release notes](https://github.com/sinonjs/sinon/releases)
- [Changelog](https://github.com/sinonjs/sinon/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sinonjs/sinon/commits)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [escape-string-regexp](https://github.com/sindresorhus/escape-string-regexp) from 1.0.5 to 3.0.0.
- [Release notes](https://github.com/sindresorhus/escape-string-regexp/releases)
- [Commits](https://github.com/sindresorhus/escape-string-regexp/compare/v1.0.5...v3.0.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [karma](https://github.com/karma-runner/karma) from 4.4.1 to 5.0.1.
- [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/v4.4.1...v5.0.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [terser](https://github.com/terser/terser) from 4.6.10 to 4.6.11.
- [Release notes](https://github.com/terser/terser/releases)
- [Changelog](https://github.com/terser/terser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/terser/terser/compare/v4.6.10...v4.6.11)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [eslint-config-hypothesis](https://github.com/hypothesis/frontend-toolkit) from 2.1.0 to 2.3.0.
- [Release notes](https://github.com/hypothesis/frontend-toolkit/releases)
- [Commits](https://github.com/hypothesis/frontend-toolkit/commits)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Implement a fallback for browsers that don't support the CSS
`mix-blend-mode` property (IE 11, Edge < 79) by merging overlapping
highlights into a single layer with uniform opacity. This prevents
overlapping highlights from affecting readability since highlights are
blended with the content underneath using normal blending in this case.

Improve the readability of highlights on PDFs by creating the highlights
in an SVG layer overlaid on top of the page's `<canvas>` instead of
using the CSS `background-color` property on the
`<hypothesis-highlight>` elements in the page's text layer.

Using an SVG placed in the DOM like this allows us to control how
the highlight is blended with the content underneath using CSS
`mix-blend-mode`. Using the `multiply` blend mode [2] means that highlights
will darken the content below rather than making dark text in the
canvas appear lighter and muddier. Additionally this approach gives us
more control over the appearance of overlapping highlights. Note that
for the custom blending to work, it is important that the SVG is in the
same stacking context as the canvas [1]

We still need to keep the `<hypothesis-highlight>` elements in the text layer
for interactive functionality (eg. interacting with highlights using the
keyboard or pointer). The SVG highlight is associated with the
`<hypothesis-highlight>` via an `svgHighlight` property so that the SVG
can be removed when the highlight itself is removed.

[1] https://drafts.fxtf.org/compositing-1/#csscompositingrules_CSS
[2] https://drafts.fxtf.org/compositing-1/#valdef-blend-mode-multiply

Convert `changedFocusedUser` into a `thunk` that dispatches both
`CLEAR_SELECTION` and `CHANGE_FOCUSED_USER`. This keeps unwanted applied
filters from being carried over into a newly-focused-user’s set of
annotations and avoids UI confusion.

Fixes #1737

Update Preact

This fixes an issue where an uncaught error thrown inside an `act` callback would
stop any `useEffect` effects from running for the rest of the test
session, which was pretty confusing to debug.

See https://github.com/preactjs/preact/releases/tag/10.4.0

Use `Injector` to initialize services

Refactor profile data access in the store