Custom theme only works when its also loaded in a custom TV

```
  'head' => array(
        'caption' => 'Title',
        'type' => 'richtext',
        'theme' => 'custom-theme'
    ),
    
```

This only shows correct when a custom TV has `{"theme":"custom-theme"}` loaded into the same template.
I guess the needed JS for the custom richtext theme is not loaded in MultiTV.
    