Handle aspect ratio changes in PiP2

Make sure to resize and update PiP bounds
if PiP2 flag is on upon an onTaskInfoChanged()
signal from the client if the requested aspect ratio
is different.

Note that we are not using config-at-end for aspect ratio change.

Also moved the movement bounds and pip bounds updates
for resize transitions into PipScheduler, to avoid
redundancy.

Bug: 361333135
Flag: com.android.wm.shell.enable_pip2_implementation
Test: atest PinnedStackTests#testChangeAspectRationWhenInPipMode
Change-Id: Ic03c01f1b6a5e204e1cc52912cb352a5684f8495