Adding flag to dynamically registered receiver.

ACTION_CLOSE_SYSTEM_DIALOG has been deprecated in T but needs to remain as exported so that it can pass tests.

Bug: 161145287
Change-Id: I1c56cee1d2fe27d5af01b6ee21f588a733a1f564
Test: No-op

libs/WindowManager/Shell/src/com/android/wm/shell/pip/tv/TvPipMenuController.java

@@ -103,7 +103,7 @@ public class TvPipMenuController implements PipMenuController, TvPipMenuView.Lis
         };
         context.registerReceiverForAllUsers(closeSystemDialogsBroadcastReceiver,
                 new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS), null /* permission */,
-                mainHandler);
+                mainHandler, Context.RECEIVER_EXPORTED);
 
         pipMediaController.addActionListener(this::onMediaActionsChanged);
     }