Make recalibration notification VISIBILITY_SECRET

See context of b/134834442

Test: Notification is only seen when device is unlocked

Fixes: 134834442
Change-Id: I977c23192b41d2a0484d03d25eee4db87ac68ba2
diff --git a/services/core/java/com/android/server/biometrics/face/FaceService.java b/services/core/java/com/android/server/biometrics/face/FaceService.java
index edb36d3..0f2b16a 100644
--- a/services/core/java/com/android/server/biometrics/face/FaceService.java
+++ b/services/core/java/com/android/server/biometrics/face/FaceService.java
@@ -193,6 +193,7 @@
                         .setAutoCancel(true)
                         .setCategory(Notification.CATEGORY_SYSTEM)
                         .setContentIntent(pendingIntent)
+                        .setVisibility(Notification.VISIBILITY_SECRET)
                         .build();
 
                 nm.createNotificationChannel(channel);