Save block panel collapsed state

[Protohominid]

Is your feature request related to a problem? Please describe.
It's frustrating when you collapse a block panel and your preference isn't saved. If the panel is long, it takes over the entire sidebar every time you select new blocks or edit a new post.

Describe the solution you'd like
If I collapse a block panel, for example, the "Styles" panel for an image block, that preference should be saved and the collapsed state persistent.

Describe alternatives you've considered
It would be even more helpful if the user could turn off certain panels altogether if they know they'll never use them.

[youknowriad]

Just noting that the panels are not collapsible anymore but it would be good to have them appear in the preferences to be able to hide them indeed.