e2e-test: fix React 17 app bootstrap for new frontend apps

Use the generated app root API when switching the scaffolded app to React 17 so the new frontend app still type-checks in E2E.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

packages/e2e-test/src/commands/runCommand.ts

@@ -437,7 +437,7 @@ async function switchToReact17(appDir: string) {
 import ReactDOM from 'react-dom';
 import App from './App';
 
-ReactDOM.render(<App />, document.getElementById('root'));
+ReactDOM.render(App.createRoot(), document.getElementById('root'));
 `,
     'utf8',
   );