Run ALS callbacks on the HAL service thread instead of main.

This part of the code was never updated when most of the face/fingerprint methods were moved off the main thread. This may not have been responsible for the bug alone, but other contention for the SensorManager on main recently seems to have made it problematic.

Flag: EXEMPT bugfix
Fix: 409958969
Test: atest BiometricLoggerTest ALSProbeTest BiometricContextProviderTest
Change-Id: I442fb6936335e1a0912451de36ac2693d9145148