Merge "Prevent apps from creating blocked channel groups" into sc-dev am: 5769ab47bf am: 89c7ef75a7 am: bfda16a013

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

Change-Id: I2fec07732a3a80b9790cf40ab81538a9b9501a5b