Limit the size of NotificationChannel and NotificationChannelGroup

Test: android.app.NotificationChannelGroupTest
Test: android.app.NotificationChannelTest
Test: cts NotificationChannelTest
Test: cts NotificationChannelGroupTest
Bug: 241764350
Bug: 241764340
Bug: 241764135
Bug: 242702935
Bug: 242703118
Bug: 242703202
Bug: 242702851
Bug: 242703217
Bug: 242703556
Change-Id: I0925583ab54d6c81c415859618f6b907ab7baada
(cherry picked from commit 3850857c)