Merge "Lower per-app NotificationChannelGroup limit." into tm-dev am: 41a2d675eb am: 3e263f2a7c am: b28523ddd6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21080663

Change-Id: I78fef76130ef92cfec8ffd4c3fa8042a0791ba1d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>