4/n: Add basic enrollment for Face

Bug: 110589286

Test: fingerprint enrolling still works
Test: enrollment flow with and without a pin set up still works properly
Test: enrollment continues when configuration changes, stops otherwise

Change-Id: I39f76c7f1a16e9533cef573f87cf4b81cb20cb18

tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensorTest.java

@@ -157,7 +157,7 @@ public class FingerprintEnrollFindSensorTest {
     @Test
     public void onActivityResult_withNullIntentShouldNotCrash() {
         // this should not crash
-        mActivity.onActivityResult(FingerprintEnrollFindSensor.CONFIRM_REQUEST, Activity.RESULT_OK,
+        mActivity.onActivityResult(BiometricEnrollBase.CONFIRM_REQUEST, Activity.RESULT_OK,
             null);
         assertThat(Shadows.shadowOf(mActivity).getResultCode()).isEqualTo(Activity.RESULT_CANCELED);
     }