Tighten CKEditor 5 kernel tests

This currently only runs the ckeditor tests, so can't move this to rtbc as-is, I personally think we should keep this in the parent issue because it's not that big.

If the drupalci.yml file can be removed please.

Done.

I had already put the parent issue this was extracted from to rtbc earlier, so if we commit this first, this is rtbc and the other one should go back to rtbc.

I already had some issues about scope in #5, because I think the original issue is not too big, with: 33 files changed, 382 insertions, 103 deletions..

However, scoping for issues is a difficult thing, so that's why I set this to rtbc

Right, I'm mostly trying to keep the other issue focused on obvious/trivial things wrt config schema, and I think that only the CKEditor 5 changes are tricky to understand.

I think this makes sense to get in separately, given the work has already done I'm committing this and then back to the other issue to tighten everything else up.

Committed and pushed 4107d4ae5c to 11.x. Thanks!

Automatically closed - issue fixed for 2 weeks with no activity.