Track usage of leak switch

Summary:
Logging to see how many people use this feature in addition to the notification logs
we keep.

Reviewed By: oprisnik

Differential Revision: D15983761

fbshipit-source-id: db64bf97d0643f2bfce25a539ee10147924ee3f8

src/plugins/fresco/index.js

@@ -423,6 +423,7 @@ export default class extends FlipperPlugin<PluginState, *, PersistedState> {
   };
 
   onTrackLeaks = (checked: boolean) => {
+    this.props.logger.track('usage', 'fresco:onTrackLeaks', {enabled: checked});
     this.props.setPersistedState({
       isLeakTrackingEnabled: checked,
     });