Ignore selectionchange events originating from <input> and <textarea> elements

[12joan]

Description
In Chrome, selectionchange events can fire when <input> and <textarea> elements are appended to the DOM, causing editor.selection to be overwritten in some circumstances. This PR addresses this issue by ignoring selectionchange events originating from these elements.

Issue
Fixes: #5791

Example
Before:

before.mp4

After:

after.mp4

Context
Although Chrome's behaviour is apparently compliant with the spec, other browsers do not behave this way, and the spec may at some point be changed to match other browsers' behaviour. See the Chromium issue for more information.

I'm fairly sure that ignoring selectionchange events from <input> and <textarea> elements will not cause other issues, since actual text selections in these elements do not affect editor.selection. However, if this PR causes a regression, feel free to revert it, since any bug it causes is likely to be more common than the one it fixes.

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 7b99695

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[dylans]

@12joan could you please verify the one failing integration test (see the changes under file changed) isn't caused by this change? thanks!

[12joan]

@dylans It looks like that test is just flaky, unrelated to this change. I ran it a few times locally on both this branch and main, and it seems to fail just as frequently on both, on roughly 7% of runs.