Fixes @Nullable issues SystemUI-tests

Test: builds
Bug: 294098415
Change-Id: I258629e15004bf5cca37e5544727c92551a10a78
Merged-In: I258629e15004bf5cca37e5544727c92551a10a78
(cherry picked from commit 852cd148d651e3abfa4cf417bfe8a88bf1fee4c0)
21 files changed