docs: enable contextIsolation in fiddles (#39613)

docs/fiddles/windows/manage-windows/frameless-window/renderer.js

@@ -1,8 +1,6 @@
-const { ipcRenderer } = require('electron/renderer')
-
 const newWindowBtn = document.getElementById('frameless-window')
 
 newWindowBtn.addEventListener('click', () => {
   const url = 'data:text/html,<h2>Hello World!</h2><a id="close" href="javascript:window.close()">Close this Window</a>'
-  ipcRenderer.send('create-frameless-window', { url })
+  window.electronAPI.createFramelessWindow({ url })
 })