WindowManager: Gate pending-transaction behind sync

Developers will reasonably assume that commands placed
in to sync or pending transaction in a given order will
reach the screen in that order. For example in this sequence:
	1. getSyncTransaction().hide(sc)
	2. Time passes
	3. getPendingTransaction.show(sc)
we would expect the SurfaceControl to end up visible. However
if the sync transaction were sent to SysUI but not yet applied
it could end up applied after, in which case the final state of
the SurfaceControl would be hidden. To solve this we listen
to the transaction committed callback for sync transactions
before sending the transaction to SysUI. In the interim
time period we gate the pending transaction on this callback.

Bug: 224438403
Bug: 227533765
Test: Existing tests pass
Change-Id: I5a99d68e134c3f10970f4635514c1a83456c4217