Merge "Add nullable annotation" into udc-qpr-dev am: 31679166 am: b33d906d

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/24544468



Change-Id: I21f2072984d2620a0012180ea8ef0ffc1f78c110
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>