Update userResizeBounds onMovementBoundsChange

When exiting PiP, onActivityUnpinned() clears
PipResizeGestureHandler#mUserResizeBounds.
So we need to make sure they are updated to
normal bounds whenever movement bounds are updated.

Movement bounds will also be updated upon entering PiP
and upon aspect ratio changes.

Bug: 381350374
Flag: com.android.wm.shell.enable_pip2
Test: enter PiP, double-tap, tap expand menu icon, enter PiP, double-tap
Change-Id: Ib2064f2b8d6a05c45aaac76071d0e1946ee097f3