Wait for the surface is gone when checking the invisibility of the activity.

- The surface still can be shown when the animation is still on-going lately.

Bug: 158087125
Bug: 157784017
Bug: 69573940
Test: atest AssistantStackTests#testTranslucentAssistantActivityStackVisibility MinimalPostProcessingTests#testNewWindowTurnsOffMinimalPostProcessing
Change-Id: Ic1423d6750337e25708fb988d8c1b8b47abb782f
3 files changed