TINY-10892: Fix deleting from P with IMG into LI would create unwanted font-styles on Chrome

[hamza0867]

Related Ticket: TINY-10892

Description of Changes:

• Fix deleting from P with IMG into LI would create unwanted font-styles on Chrome

Pre-checks:

• Changelog entry added
• Tests have been added (if applicable)
• Branch prefixed with feature/, hotfix/ or spike/

Review:

• Milestone set
• Docs ticket created (if applicable)

GitHub issues (if applicable):

[TheSpyder]

I'll review it when the unnecessary format changes are reversed.

[spocke]

This fix adds some weird undo levels. I really should have looked into this earlier since I think we just need to add a ElementType.isListItem here: https://github.com/tinymce/tinymce/blob/main/modules/tinymce/src/core/main/ts/delete/BlockMergeBoundary.ts#L60 that is whats preventing the the merge blocks code from working with lists. There might be issues with merging list items into list items since some of that is overrided in the lists plugin so that you would outdent the list instead. But a complete override is better than trying to let the browser do it's thing, have a bunch of tracking states on that easier to test and easier to predict the behavior.

[TheSpyder]

Well! That was quite a lesson in learning what the editor is capable of before building something that already exists 😂

I'm not sure I knew it existed either, to be fair.

[TheSpyder]

It's no longer really a chrome test, nor it is a quirks test 🤔

I'm happy to keep the test, just rename it (and remember the describe call includes the name).

[TheSpyder]

I just saw #9648. We don't need two PRs for the same fix, as release/7 will be merged to main after release.

[hamza0867]

Closing this PR as #9648 is the PR that should have existed to begin with.