Clean up the reparented leash at the end of the transition.

This is to avoid leaking leashes and only temporary until we remove
the wrapper (b/397180418). Also because of the wrapper, the
Transaction might throw (in which case the leash doesn't leak as
it's been already released) so it's best effort.

Bug: 390422470
Flag: com.android.systemui.move_transition_animation_layer
Test: atest ActivityTransitionAnimatorTest
Change-Id: I74092d1cd5ed480a37e0d1e296dc3270de56bb96