Use updated source rect hint in PIP exit animation

This change does a couple of things:
1. Make sure to use the latest sourceRectHint when starting the exit
animation.
2. Remove deferral of the call to ITaskOrg#onTaskInfoChanged from
ATM#setPipParams so that the updated rect hint can be received in
PipTaskOrganizer without waiting for WindowContainer#prepareSurfaces
to be called.

Bug: 167447693
Test: exit animation performs uncrop and scale using new rect
provided by test app after re-layout on exit PIP

Change-Id: I2a2be39f65adf5ee88f3351950d6707e8e53f089