Configures FingerprintService to use FingerprintStateCallback to notify

clients of fingerprint sensor state changes

Implements FingerprintStateCallback class to receive notifications of
changes in fingerprint state, and updates ServiceProvider method
signatures and Fingerprint21 accordingly to use this callback type for
authentication, enrollment, and other side fps events. Also defines
FingerprintStateListener class to forward state changes in
fingerprint-related events from FingerprintService to the
SideFpsEventHandler, which defines logic for interactions
between power button state and side fps state.

Test: adb shell dumpsys fingerprint

Bug: 183997671
Change-Id: I9a44e2f31648590c0d0d4d065b68c39c9f204051