[Console] Add a setting to disable the a11y overlay

[yuliacech]

Summary

Fixes #16139

This PR adds a setting in Console that allows to disable the a11y overlay. The default will be set to enabled so that the default behaviour should not change. A user can disable the overlay in their browser and the setting is saved in local storage. So that other users are not affected by that change.

The reason to allow disabling the overlay is that it can be flaky and sometimes it's displayed when not intended. The code relies on querySelector (see this file) so I think that causes the flakiness and that is very difficult to test reliably.

Screenshot

A11y overlay (no changes)

Settings modal with the new option to disable the a11y overlay

How to test

1. Start Kibana and navigate to the Console
2. Press ESC when textarea is focused and now autocomplete popup is displayed to see the a11y overlay
3. Open the Settings modal and disable the a11y overlay
4. Press ESC in the textarea again to see that no overlay is now displayed
5. Check that the value is persisted in the local storage

Flaky test runner
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/2346

Checklist

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/platform-deployment-management (Team:Deployment Management)

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 7471910

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
console	417.9KB	418.5KB	+586.0B

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
console	26.7KB	27.2KB	+483.0B
esUiShared	154.7KB	154.8KB	+45.0B
total			+528.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	19	21	+2
securitySolution	414	418	+4
total			+6

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	20	22	+2
securitySolution	498	502	+4
total			+6

History

• 💚 Build #132192 succeeded 2415193
• 💔 Build #131831 failed d111027

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@elasticmachine merge upstream

[sabarasaba]

Thanks for working on this @yuliacech! I've tested locally and code changes lgtm 🚀

[yuliacech]

Thanks a lot for your review, @sabarasaba!

[yuliacech]

Merging this after running the flaky test runner https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/2349 twice with 200 iterations.

[yuliacech]

Also confirmed the ui copy with @alaudazzi