DeskClock: Fix alarm clock screen show black  when screen locked; am: 504dfe5e4b am: 5e8ac047f6

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/DeskClock/+/12409395

Change-Id: I78bf89d5b193b3cda2ac39371e78d495db445eec