Merge ""Hide silent notifications in status bar" should apply to silent...

Merge ""Hide silent notifications in status bar" should apply to silent conversations,too" into udc-dev am: b2540493

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22344026



Change-Id: I0ca89b1784ba5f8a2d6b8f632855e72bda59ccfd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>