Revert "Add the FLAG_IMMUTABLE flag for creating a PendingIntent"

This reverts commit 334968c113.

Reason for revert: Bug: 170280415

Change-Id: Idaa269406d6c1609c75f0dfba1f7fa9daf979101

src/com/android/settings/slices/CustomSliceable.java

@@ -95,7 +95,7 @@ public interface CustomSliceable extends Sliceable {
                 .setData(getUri())
                 .setClass(context, SliceBroadcastReceiver.class);
         return PendingIntent.getBroadcast(context, 0 /* requestCode */, intent,
-                PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE);
+                PendingIntent.FLAG_UPDATE_CURRENT);
     }
 
     @Override