[Dashboard] [Controls] Selecting option in view mode causes unsaved changes bug in edit mode

[Heenawter]

Describe the bug:

When making a selection on an options list in view mode and then switching to edit mode, unselecting those options will not clear unsaved changes as it should.

Steps to reproduce:

1. Open a sample dashboard in view mode
2. Make a selection on one of the controls
3. Switch to edit mode
4. Notice that the unsaved changes badge shows up, as expected
5. Unselect the option from step 1
6. Notice that the unsaved changes badge is not cleared, even though it should be 🔥

Screenshots (if relevant):

Screen.Recording.2022-10-19.at.9.07.04.AM.mov

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[ThomThomson]

I wonder if this is the bug that you found in #140739 ?

[Heenawter]

@ThomThomson It totally is, sorry! Didn't make the connection.

I'll likely be fixing this in #142780 because I had to introduce that custom diffing system anyway, and it seems like this bug is caused by (from a very early investigation) an empty array being "different" than the undefined key :P

[ThomThomson]

Hahaha of course! We really do need to move this diffing over to the embeddable side...