Fix errorprone warnings that should be errors am: 27db4326e4 am: 24d17c9351

Original change: https://android-review.googlesource.com/c/platform/packages/apps/DocumentsUI/+/2256451

Change-Id: I06955c2e2915c345f748da5ec20ae41bebef5ae3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>