Merge "Disallow setting invalid importance when updating a...

Merge "Disallow setting invalid importance when updating a NotificationChannel" into udc-dev am: 8128beb1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21478864



Change-Id: I9719891a8859e3b87b2be92d5b4bc00bca4babc5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>