Settle auto PiP transaction in WindowContainerTransaction

At the end of autoEnterPip transition, followings happen in sequence
- Transition finishes in Launcher side, which operates on the
  animation leash
- RecentsAnimationController.TaskAnimationAdapter#onCleanup has the final
  chance to set the Task leash
- PipTaskOrganizer gets onTaskAppeared callback and commits Task into
  pinned mode

What's been changed here
- Transition in Launcher no longer in charge of settle the final transaction
- RecentsAnimationController.TaskAnimationAdapter#onCleanup sets the
  Task leash to be in sync with the final state in Launcher side
- PipTaskOrganizer commits the final leash transaction together with
  WindowContainerTransaction that enters PiP

Known issue: transition from landscape is not polished

Video: http://rcll/aaaaaabFQoRHlzixHdtY/hT5SXvaCy28P4UtfuoKiDw
Bug: 181342797
Test: see video
Change-Id: Ieabd6991ea5174099714ec22970198bebde1e336