docs: fix fiddles (#39060)

* refactor: replace Array.prototype.forEach.call with plain for-of

* fix: add missing contextIsolation: false

* fix: open links in default browser

docs/fiddles/native-ui/external-links-file-manager/path-in-file-manager/main.js

@@ -8,6 +8,7 @@ function createWindow () {
     height: 400,
     title: 'Open Path in File Manager',
     webPreferences: {
+      contextIsolation: false,
       nodeIntegration: true
     }
   }