[PiP2 on Desktop] Enter PiP with bounds change animation.

Recall: http://recall/clips/d4b0542f-424a-436a-8f17-a1eeb0d9e91b

This CL allows enter PiP on Desktop mode with bounds change animation.
If the task is minimizing to PiP, a PiP transition is started instead of
a minimize transition. If the PiP transition is aborted down the line, a
minimize transition will then be started.

Bug: 378745750
Bug: 377582265
Test: atest DesktopTasksControllerTest
Flag: com.android.window.flags.enable_desktop_windowing_pip

Change-Id: Icf309eaa4aa5092839b221ee2774eb309f112202