addComponent function
        
Future<void> 
addComponent(
    
    
- BuildContext context,
- AppModel app,
- String? componentName,
- EditorFeedback editorFeedback,
Implementation
Future<void> addComponent(BuildContext context, AppModel app,
    String? componentName, EditorFeedback editorFeedback) async {
  var appId = app.documentID;
  if (componentName == null) {
    openErrorDialog(app, context, '$appId/_error',
        title: 'Problem', errorMessage: 'Component name is null');
  } else {
    var component =
        Apis.apis().getRegistryApi().getComponentSpecs(componentName);
    if (component == null) {
      openErrorDialog(app, context, '$appId/_error',
          title: 'Problem',
          errorMessage: 'Component specs for $componentName not found');
    } else {
      component.editor.createNewComponent(app, context, editorFeedback);
    }
  }
}