[LE] Launch the dialog for the user to broadcast or find broadcast

- Launch the broadcast dialog from entry point in Media Volume Slice

    - Fix the broadcast dialog to follow the dialog style

    - Start broadcast and launch the MediaOutputBroadcastDialog from
      broadcast dialog

Bug: 229577518
Test: manual test
Change-Id: I1329b3f35b03afc441142494df883ae17f373656

src/com/android/settings/media/MediaOutputIndicatorWorker.java

@@ -161,7 +161,7 @@ public class MediaOutputIndicatorWorker extends SliceBackgroundWorker implements
         return mLocalMediaManager.getCurrentConnectedDevice();
     }
 
-    String getPackageName() {
+    public String getPackageName() {
         return mPackageName;
     }