Merge "Fix potential memory leak by setting mControllers = null" into sc-v2-dev am: 96f3f2214c

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16367281

Change-Id: Iaee380e7e3ee610f0d06cbb001bf45f18c945ee6