Reset isStuffed when buffer stuffing recovery ends

Since it is possible for RenderThread to still be blocked
on dequeueBuffer while buffer stuffing recovery is happening,
the isStuffed state can remain true even after the animation
has ended, causing the subsuequent animation(s) to behave
as if recovery needs to continue. Reset the boolean.

Bug: b/383893971
Test: Manually check perfetto traces, presubmit, SysUI performance tests
Flag: android.view.flags.buffer_stuffing_recovery
Change-Id: Ia07c526085316cca9d7e8a2501e33cdd2bd2bdd2