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

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

Change-Id: I803d9876d18e78324a493f6ae1d3dc8795e62e60
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>