Make the pending intent immutable.

Bug: 173157883
Test: atest SystemActionPerformerTest
Change-Id: I291e1ad768e8a4fc873926a82f689c45cc51819e

packages/SystemUI/src/com/android/systemui/accessibility/SystemActions.java

@@ -400,10 +400,8 @@ public class SystemActions extends SystemUI {
                 case INTENT_ACTION_ACCESSIBILITY_SHORTCUT: {
                     Intent intent = new Intent(intentAction);
                     intent.setPackage(context.getPackageName());
-                    // TODO(b/173157883) Please replace FLAG_MUTABLE_UNAUDITED below
-                    // with either FLAG_IMMUTABLE (recommended) or FLAG_MUTABLE.
                     return PendingIntent.getBroadcast(context, 0, intent,
-                            PendingIntent.FLAG_MUTABLE_UNAUDITED);
+                            PendingIntent.FLAG_IMMUTABLE);
                 }
                 default:
                     break;