Merge "Removing back-button alpha animation code" into tm-qpr-dev am: 676d19c1

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/19915471



Change-Id: I2958d9cd87323c5a3934904120d550fbb2d2f411
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>