[Rich Content Editor] Add Canvas Studio button to new RCE Toolbar

The Canvas Training Portal advertises that there should be a Canvas Studio button on the RCE toolbar, with the standard Canvas Studio icon, but the button is not present on the new RCE toolbar.  Instead, you must click the "apps" button and the locate Studio from a list.  Since Studio is deeply integrated with Canvas, it would be ideal to show the Studio button as a standalone on the new RCE toolbar.