Merge "Fix NullPointerException of using null mWallpaperConnection" into ub-launcher3-master am: 01c38e6101 am: f87965d141

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/WallpaperPicker2/+/11699850

Change-Id: I86e8286c9fca6ae5ce42f4c357d3bf5a45247417