Merge "Clarify reasons for notification removal." into udc-dev am: ebf1af85 am: b39bfaf3

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24211145



Change-Id: I003e729b41fe82a2ee9e15416934c8b81a2187cc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>