dial-in-info: fix bundle bloat

The direct import sidesteps many chained-effect imports, halving the bundle
size.

react/features/invite/components/dial-in-info-page/DialInInfoApp.web.js

 import { DialInSummary } from '../dial-in-summary';
 
 import NoRoomError from './NoRoomError';
-import { Platform } from '../../../base/react';
+import Platform from '../../../base/react/Platform.web';
 
 document.addEventListener('DOMContentLoaded', () => {
     const { room } = parseURLParams(window.location, true, 'search');