docs: enable contextIsolation in fiddles (#39613)

docs/fiddles/native-ui/dialogs/error-dialog/index.html

@@ -73,9 +73,6 @@ ipcMain.on('open-error-dialog', (event) => {
       </div>
     </div>
 
-    <script>
-      // You can also require other files to run in this process
-      require("./renderer.js");
-    </script>
+    <script src="renderer.js"></script>
   </body>
 </html>