Configures SideFpsEventHandler to handle PhoneWindowManager behavior in

response to side fingerprint sensor state changes

Implements SideFpsEventHandler to handle interactions between power
button state and side fps state in PhoneWindowManager, displaying
ConfirmScreenOffDialog when the power button is pressed during
fingerprint enrollment. Uses IFingerprintAuthenticatorsRegisteredCallback
to determine when all dependencies are ready to begin checking side fps state.

Test: Press power button during fingerprint enrollment

Bug: 183997671
Change-Id: If02d74e2d8d9f01642b848743049cdec447f60cf