Auto-link undo correction

[kbinieda]

📝 Provide detailed reproduction steps (if any)

1. type "https://ckeditor.com abc" in content (hyperlink should be created for ckeditor.com, while "abc" still remains as text, which is fine)
2. slowly (one character at a time) hit backspace to remove " abc" text (including space).
3. Instead of removing space, editor undo character removal to initial "https://ckeditor.com abc" situation.

✔️ Expected result

just "https://ckeditor.com" in editor

❌ Actual result

"https://ckeditor.com abc" in editor

[kbinieda]

@arkflpc @scofalik While working with the task, I've found that in various places requestUndoOnBackspace function is enclosed in enqueueChange while in some other it is not. Is there a reason to that?

autolink.js
model.enqueueChange( () => { deletePlugin.requestUndoOnBackspace(); } );

automediaembed.js
editor.plugins.get( 'Delete' ).requestUndoOnBackspace();

[arkflpc]

requestUndoOnBackspace should be called after current Batch is applied. So if it happens inside model.change() or mode.enqueueChange(), it has to be wrapped with another model.enqueueChange() to delay its execution to another Batch. If not, it's not needed.