Use a CDN and updated endpoints to load extensions and behaviors (#7644)

Only show in developer changelog

Author: 4ian

newIDE/app/.storybook/main.js

@@ -18,5 +18,6 @@ module.exports = {
       },
     },
     '@storybook/preset-create-react-app',
+    'storybook-addon-mock',
   ],
 };