Clean up old flipper rating system

Summary:
Found some unused code from the rating prototype before switching to itsr.
Deleting it.

Reviewed By: cekkaewnumchai

Differential Revision: D18298155

fbshipit-source-id: 3529db17494f4f5bf7d7841460203d1c3856299a

src/dispatcher/tracking.tsx

@@ -48,8 +48,6 @@ export default (store: Store, logger: Logger) => {
       clients,
     } = store.getState().connections;
 
-    const {flipperRating} = store.getState().application;
-
     if (!selectedDevice || !selectedPlugin) {
       return;
     }
@@ -73,7 +71,6 @@ export default (store: Store, logger: Logger) => {
       plugin: selectedPlugin,
       app,
       sdkVersion,
-      flipperRating,
     };
 
     // reset dropped frames counter