Backspace into list item should create hard break - not a second paragraph in the list item

#3568 introduced a new behavior. Now when you press backspace at the beginning of a paragraph it will add a hard break while joining the paragraph with the previous one.
This works nicely in general.

However when in a list and i press enter but then i decide i want to go back to the previous list item I now have to press backspace three times:

• remove the new list item, end up on a second paragraph in the first
• join the two paragraphs, now split by a hard break
• remove the hard break to get into the first line of the list item.

I think it would be nice if backspacing into a list item would directly land you after a hard break rather than in a second paragraph in that list item.

Originally posted by @max-nextcloud in https://github.com/nextcloud/text/issues/3568#issuecomment-1350432949

Start by reproducing the list-item backspace behavior described here and compare it with the behavior introduced in issue #3568. Done means pressing backspace after creating a new list item reaches the previous item after one hard break, without requiring the extra paragraph and hard-break removal steps.