Add SoundTrigger event types for logging

- Encapsulate event types for use with EventLogger
- Separate events into service-wide and sessioned events
- Enumerate event types for all methods
- Optional error string for distinguishing error events

Bug: 272147641
Fixes: 278138038
Test: atest SoundTriggerEventTest
Change-Id: I74075402f4c82aeb79444fd4d5ed17c38d97542e