Clean up App duplication

Summary: fb/App didn't really have a difference with fb-stubs/App, except that one checks for employee presence. However, since that is already controlled by config.checkFbEmployee, de-duped this to a single `<AppWrapper>` component, making the code a bit more easy to follow

Reviewed By: priteshrnandgaonkar

Differential Revision: D25824521

fbshipit-source-id: 8e16f0b29ec5d12475eaf14acd9dbc7df91191a2

desktop/app/src/Client.tsx

@@ -14,7 +14,7 @@ import {
   FlipperDevicePlugin,
 } from './plugin';
 import BaseDevice, {OS} from './devices/BaseDevice';
-import {App} from './App';
+import {LegacyApp} from './chrome/LegacyApp';
 import {Logger} from './fb-interfaces/Logger';
 import {Store} from './reducers/index';
 import {setPluginState} from './reducers/pluginStates';
@@ -124,7 +124,7 @@ export interface FlipperClientConnection<D, M> {
 }
 
 export default class Client extends EventEmitter {
-  app: App | undefined;
+  app: LegacyApp | undefined;
   connected: boolean;
   id: string;
   query: ClientQuery;