Merge "WallpaperManagerService:fix potential null pointer exception in onDisplayRemoved method." into main am: a5cab7b8dc am: a05ca86a62

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3133377

Change-Id: Idb272126827c072c852b33133b31f431ba6ae254
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>