Provide access for metrics->Java Bundle conversion

provide 'friend' access for the class that converts Media Metrics
properties into a Java Bundle to be handed to users through local APIs.
Actual code to do conversion is in frameworks/base/

Bug: 34716157
Test: compilation passes
diff --git a/include/media/MediaAnalyticsItem.h b/include/media/MediaAnalyticsItem.h
index a78aa8b..f050e7f 100644
--- a/include/media/MediaAnalyticsItem.h
+++ b/include/media/MediaAnalyticsItem.h
@@ -40,6 +40,7 @@
 
     friend class MediaAnalyticsService;
     friend class IMediaAnalyticsService;
+    friend class MediaMetricsJNI;
 
     public: