Merge "[4/n] Add Apply Button to grid preview page" into udc-qpr-dev am: 8e191fd9

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/24435476



Change-Id: I199e72e3dc11ba46d65e15e422542b55c57e87a0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>