4/n: Make CoexCoordinator multi-sensor-aware

CoexCoordinator now knows whenever specific types of sensors are
started/stopped.

Note that this change is still a no-op and does not affect any
existing behavior.

Bug: 193089985
Test: atest com.android.server.biometrics
Test: inspect logs
Change-Id: I6f1980ba02febfa0a866e2684fdfc23a1ca664e1