Merge "Prevent apps from creating blocked channel groups" into sc-dev am: 5769ab47 am: 89c7ef75 am: 5c86f54b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16623717

Change-Id: I84c26ebc06d9cae5e57c055f008d7c43bc928937