Bug: Deleting first list item with nested list items and no siblings of same depth results in a strange cursor position

When deleting a list item that has no next sibling of the same depth, the selection ends up in a weird state

Lexical version: 0.9.1 (looks to occur on current lexical playground too)

## Steps To Reproduce

Start with a list item like the following:
- ABC
- XYZ

Delete the ABC text and then hit backspace one more time to delete the topmost list item

Cursor is now in a weird state

## The expected behavior
I would expect the cursor to be at the top left of the editor

Reproduce the nested-list deletion sequence in the current Lexical playground, starting with a top-level item containing only a nested item. Trace the list deletion and selection handling; the fix is complete when deleting the top-level item leaves the cursor at the editor's top-left position.

Written by the indexing model from the issue text.