Make biometric PendingIntent immutable

Fixes: 172207250
Test: Builds
Change-Id: I75688873ca74408c70559ca9ec3717a38bba0f60

src/com/android/settings/biometrics/MultiBiometricEnrollHelper.java

@@ -80,7 +80,7 @@ public class MultiBiometricEnrollHelper {
                         mActivity.getIntent());
                 fpIntent.putExtra(ChooseLockSettingsHelper.EXTRA_KEY_GK_PW_HANDLE, mGkPwHandle);
                 final PendingIntent fpAfterFaceIntent = PendingIntent.getActivity(mActivity,
-                        0 /* requestCode */, fpIntent, 0 /* flags */);
+                        0 /* requestCode */, fpIntent, PendingIntent.FLAG_IMMUTABLE);
                 faceIntent.putExtra(EXTRA_ENROLL_AFTER_FACE, fpAfterFaceIntent);
             }