Fixing back animation for container views

> Looking up views during back instead of holding the reference
  This allows back animation even if Launcher restarts
> Fixing back animation not working with progressive back
> Fixing container animation overriding Launcher cookie used be gestureNav

Bug: 365866488
Test: Verified manually by enabling flag
Flag: com.android.launcher3.enable_container_return_animations
Change-Id: Ic235b238cca6a31e9a5502200ff6b07c72b4e4d7
4 files changed