[RN] Remove unused code

react/features/mobile/full-screen/middleware.js

 // @flow
 
-import { StatusBar } from 'react-native';
 import { Immersive } from 'react-native-immersive';
 
 import { APP_WILL_MOUNT, APP_WILL_UNMOUNT } from '../../base/app';
     // throws on other platforms.
     if (Platform.OS === 'android') {
         fullScreen ? Immersive.on() : Immersive.off();
-    } else {
-        // On platforms other than Android go with whatever React Native itself
-        // supports.
-        StatusBar.setHidden(fullScreen, 'slide');
     }
 }