Refactor swipe-pip-to-home transition

With the defer config dispatch till transition end
redesign applying transforms on activities instead
of task leashes in Core, we can drastically simplify Shell
code for handling TRANSIT_PIP jumpcut transition at the end
of swipe PiP to home CUJ.

We can also re-enable PiP interaction earlier since there is
no need to wait for app draws through TransactionCommittedListener.

Bug: 202201326
Flag: com.android.wm.shell.enable_pip2
Test: atest PinnedStackTests
Change-Id: I147fbf7d0878a9fbec28fcbc9dd3051a5cd7558f