Fixes crash when returning to lock screen tab (1/2). am: b521b0e668 am: 05ff61904f

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/20986976

Change-Id: Ib96c57a16160b553446db18131c93acf664160e8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>