Refactor FingerprintDialog to BiometricDialog

This CL changes FingerprintDialog into the more generic
BiometricDialog, which OEMs will be able to extend as necessary to
provide support for alternate biometric modalities.

Bug: 74831038
Test: m -j50 FingerprintDialog (from the associated CL on this topic)
      The app works and authenticates successfully.
Test: make update-api -j56

Change-Id: Ic398ef0a0b448be68dbe3330b30779f93f567243