Don't render hidden widgets in markdown visual editor (#1414)

src/components/EditorWidgets/Markdown/MarkdownControl/VisualEditor/Shortcode.js

@@ -66,6 +66,7 @@ class Shortcode extends React.Component {
       onOpenMediaLibrary,
       onRemoveInsertedMedia,
     } = this.props;
+    if (field.get('widget') === 'hidden') return null;
     const value = shortcodeData.get(field.get('name'));
     const key = `field-${ field.get('name') }`;
     const Control = getEditorControl();