Merge "Ignore null action in AppStateTrackerImpl." into main am: c809cb93b3 am: 4f9c99ace2

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3324453

Change-Id: Ie9c2363b128a8df12eb1160c89762a1e2ad6974c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>