[automerger skipped] Fixes @Nullable issues SystemUI-tests am: b9b9aa5e am:...

[automerger skipped] Fixes @Nullable issues SystemUI-tests am: b9b9aa5e am: 5c67c7c5 -s ours am: ccea6211 -s ours

am skip reason: Merged-In I258629e15004bf5cca37e5544727c92551a10a78 with SHA-1 852cd148 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24592301



Change-Id: I32182ac05b5ffd3ede1449a0a26c601be85bbd47
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>