Add onUdfpsUiEvent() and callbacks on overlay shown in FingerprintManager.

This CL renames onUiReady() to onUdfpsUiEvent() for the event of overlay
shown in FingerprintManager and notifies the mService for calling
corresponding callbacks.

Bug: 280718879
Test: atest UdfpsControllerTest
Change-Id: Ifcd11becb75d81259215d24172636f8f7bb7b6ee