Improve the release of predict_back animaton leash

Seems the predict_back nimation leash cant be released in time after
gesture animation already finsihed, and it will keep for long time it
may cause SurfaceFlinger memory loading high and layer count too much.

Flag: EXEMPT bugfix
Bug: 370247136
Test: repeatly open settings and gesture predict back to home launcher
(cherry picked from https://partner-android-review.googlesource.com/q/commit:7c1a0cf0be835656dbc9897535b5ee55ba1ea33f)
Merged-In: I51845842decf47a79da755418c61a227eae6474a
Change-Id: I51845842decf47a79da755418c61a227eae6474a