Remove MediaOutputPanel and MediaOutputSlice

Bug: 174192979
Test: build pass
Change-Id: Ibbbb9e7865ae991d13cd7a2d4fb9c5c75a689dea

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

@@ -87,7 +87,7 @@ public class MediaOutputIndicatorSlice implements CustomSliceable {
 
     @Override
     public Intent getIntent() {
-        // This Slice reflects active media device information and launch MediaOutputSlice. It does
+        // This Slice reflects active media device information and launch MediaOutputDialog. It does
         // not contain its owned Slice data
         return null;
     }