Merge "Prevent NPE inside AllAppsTransitionController" into sc-dev am: d60299e19f

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/13756046

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I409e9c7927007a0e93b7abdd3f91b22a10e48122