Check for null in addition to instanceof Face

We only send a Face object if the client holds the MANAGE_BIOMETRIC
permission. Otherwise we send null. Fixes the issue where clients that
don't have the MANAGE_BIOMETRIC permission don't receive
onAuthenticationSucceeded callback.

Test: Builds
Change-Id: If1742570ebe914d0ba7da17e60655fed3c9a4b39

services/core/java/com/android/server/biometrics/face/FaceService.java

@@ -485,7 +485,7 @@ public class FaceService extends BiometricServiceBase {
                 BiometricAuthenticator.Identifier biometric, int userId)
                 throws RemoteException {
             if (mFaceServiceReceiver != null) {
-                if (biometric instanceof Face) {
+                if (biometric == null || biometric instanceof Face) {
                     mFaceServiceReceiver.onAuthenticationSucceeded(deviceId, (Face)biometric);
                 } else {
                     Slog.e(TAG, "onAuthenticationSucceeded received non-face biometric");