Merge "Log a notification update when fields such as importance or ranking...

Merge "Log a notification update when fields such as importance or ranking score are updated." into sc-qpr1-dev am: e97b0e8f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15890028

Change-Id: I0a108e08706e28f689dbf8125b643e975f9164be