Merge "Remove PreviewFragment (2/3)" into udc-qpr-dev am: 8d49225c18

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/24526538

Change-Id: I433a9cec94f5dc4daf6bc093c5db4b204607d5d8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>