Allow action visibility to be toggled.

Adding the bit to the ActionButtonViewModel instead of the appearance
to make it simpler to toggle visibility without having to re-provide all
the labels/images each time.

Bug: 329659738
Test: manual test with toggling visibility in the actions provider after
      various delays.
Flag: ACONFIG com.android.systemui.screenshot_shelf_ui DEVELOPMENT
Change-Id: I3c5cae3ff91b364c427394d801fb09a08bdea803
Merged-In: I3c5cae3ff91b364c427394d801fb09a08bdea803