App can remain foreground forever without showing any notification and can bypass one time permissions. android.app.cts.NotificationManagerTest#testNotify_blockedChannelGroup

In createNotificationChannelGroup of PreferencesHelper.java, there is a possible way for a service to run in foreground without user notification due to improper input validation. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.