Rework how sheet behaviors work on cells where editor is open

[luke-quadratic]

Current behavior: if a Python cell is open as editor you can't delete a selection of cells that include that open in editor selection (you can however cut! at the moment cutting just deletes every cell around it in the selection and leaves code cell, but delete deletes nothing)

Desired behavior: with editor open be able to delete and cut all cells including the editor cell, would include cutting the code cell and moving it

Considerations: for cut to work properly it needs to save code first in editor

[luke-quadratic]

Notice this behavior a lot when trying to cut and paste charts. Very common because charts need to be relocated/aligned in charts commonly. Normal code cells less common. It works out funny because you end up accidentally pasting the chart and it not cutting so you have charts overlapping.

[luke-quadratic]

this behavior works as intended now