Add timeout to abort PiP if needed

Make sure we abort enter-PiP via abort
upon a timeout after moveActivityToPinnedRootTask()

We remove any timeout callbacks set up if we detect
that activity windowing mode is being changed directly
in WindowOrganizerController (applies to PiP1 only) and
if the windowing mode is requested to be the same as its task.

Bug: 334038395
Test: N/A until a proof-of-concept repro path is produced
Change-Id: I334bb336e11c774a4e22d646e16ba99cace42a7d