Client fixes

Summary:
Event emitter was typed any. Therefore, Client extended any and thing went south.
removing the explicit any type and fixing flow errors.

Reviewed By: jknoxville

Differential Revision: D15987630

fbshipit-source-id: 9456149d46f839d9579fcc2671ab2a82935fc23a

src/dispatcher/tracking.js

@@ -11,6 +11,7 @@ import {performance} from 'perf_hooks';
 
 import type {Store} from '../reducers/index.js';
 import type {Logger} from '../fb-interfaces/Logger.js';
+import type Client from '../Client';
 
 export default (store: Store, logger: Logger) => {
   let droppedFrames: number = 0;