This commit adds the plumbing which sends the signals from the API
to the component in SysUI. The dialog will be implemented in another
CL in this topic.
Bug: 67497360
Test: Modify Settings to use the new API
Test: FingerprintDialogImpl is able to notify FingerprintDialog clients
of user events
Test: System dialog is dismissed when client application is killed
unexpectedly
Test: Open FP settings, lock device, authenticate, authenticate. Repeat
Change-Id: Id28ec9691646bed765dc069cceb4678d9f6db92e
aae4a15a22