Revert "Revert "Specify explicitly FLAG_IMMUTABLE for PendingIntent""

This reverts commit 13ebec46a5.

Reason for revert: To fix the NPE issue

Specify explicitly FLAG_MUTABLE for PendingIntent

This change is to specify explicitly FLAG_MUTABLE to the pendingIntent
since this intent is working with inline reply.

Bug: 172894032
Test: manual test
Change-Id: I5fdcf175307cec5e0e96b33d711221be839e1357

src/com/android/settings/fuelgauge/batterytip/BatteryTipUtils.java

@@ -124,7 +124,7 @@ public class BatteryTipUtils {
             throws StatsManager.StatsUnavailableException {
         final Intent extraIntent = new Intent(context, AnomalyDetectionReceiver.class);
         final PendingIntent pendingIntent = PendingIntent.getBroadcast(context, REQUEST_CODE,
-                extraIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+                extraIntent, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_MUTABLE);
         statsManager.setBroadcastSubscriber(pendingIntent,
                 StatsManagerConfig.ANOMALY_CONFIG_KEY, StatsManagerConfig.SUBSCRIBER_ID);
     }