Adding System Usages to AudioAttributes

- Converted USAGE_CALL_ASSISTANT to system usage
- Added USAGE_EMERGENCY, USAGE_SAFETY, USAGE_VEHICLE_STATUS, and
USAGE_ANNOUCEMENT as new system usages
- Updated JNI to understand how to set system usages

Bug: 141006627
Test: atest AudioAttributesTest
Change-Id: I4bccf1a7c45df98a15d8944cd316f4c05ffaa3ec