Fix mismatched state between SystemUI and FingerprintService

This CL fixes issues that lead to occasional fingerprint enrollment
state inconsistencies between SystemUI and FingerprintService:

1. Unordered processing of "onAllAuthenticatorsRegistered" and
   "onEnrollmentsChanged" in AuthController.
2. Data races in AuthController caused by unguarded access between the
   main and incoming Binder threads.

Bug: 207726663
Test: atest AuthControllerTest
Test: add artificial 10 sec delay to fingerprint HAL start up
Change-Id: I9dcb80443996fcdefcba976b0f60cc6f2d036afd