aaudio: do not use RAW flag for notifications, alarms

The RAW flag was preventing the RINGTONE, NOTIFICATION, ALARM
and other usages from using dual sinks in the low-latency, Legacy path.

Now, the RAW flag will only be used for USAGEs that require
the lowest possible latency, ie. MEDIA and GAME.

Bug: 315834972
Test: see repro steps at b/315834972#comment12
Change-Id: Ie253bbe11e965c358b0fbc35641183b145b8a0fc