Merge "Fixes activity leak in Wallpaper Picker." into udc-dev am: b7c4aec8b0 am: 069dc50285 am: 155602ffa4

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/23439007

Change-Id: I6b0d6a50a916deb2d30025312fc83a94d2fa8aa4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>