Ignores entering PiP animation on seamless rotation

- Added onFixedRotationStarted/onFixedRotationFinished callback in
  DisplayWindowListener
- onFixedRotationStarted shall be called before onTaskAppeared for PiP
- When onTaskAppeared is received in PipTaskOrganizer, we defer the
  entering PiP transition if fixed rotation is ongoing
- When onFixedRotationFinished is received in PipTaskOrganizer and the
  entering PiP transition is deferred, schedule an immediate
  transition to PiP to make sure all the expected callbacks from
  PipTaskOrganizer are still being sent

Video: http://go/recall/-/aaaaaabFQoRHlzixHdtY/bb8HjJvMZKtpN8YTPKZXmj
Bug: 153861223
Test: manually enter PiP from Play Movies / YT fullscreen
Test: atest ActivityRecordTests \
            RecentsAnimationControllerTest \
            ActivityTaskManagerServiceTests \
            PinnedStackTests
Change-Id: I0dea905d610e2387af56b611be5f93518cc9a153