Use a log tag that can be enabled in ManagedServices subclasses

Because NotificationListeners is an inner class, the tag was "NotificationManagerService$NotificationListeners", which setprop doesn't accept.

Bug: 359126464
Test: manual with adb logcat
Flag: EXEMPT Trivial
Change-Id: If564888cdd67610052e9320f97dc2f0b800ecafd