Remove the usage of private style attributes am: 8f68b26598 am: 3022840294

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/20334755

Change-Id: Idd335e5fe30f21488195410e6ccbae0ae718f4d6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>