Schedule PIP mode changes at the beginning/end of the transitions.

- When transitioning from fullscreen to PiP, ensure all PiP/MW/Config
  changes come after the transition completes, and inversely, from PiP to
  fullscreen, ensure that all changes come before the transition up starts
- Add a series of tests to verify the callback state when the animation
  is canceled
- Also fixes an issue where the surface is preserved when we don't want

Bug: 37169080
Bug: 37103000
Test: bit FrameworksServicesTests:com.android.server.wm.BoundsAnimationControllerTests
Test: android.server.cts.ActivityManagerPinnedStackTests
Change-Id: I6425c95df358358ed76d9cc8a130606c2124062e