code: func (m *Messenger) DeleteGetStartedButton() error {
  	result, err := m.changeThreadSettings(http.MethodDelete, &threadSettings{
  		Type:  settingTypeCallToActions,
  		State: threadStateNew,
  	})
  	if err != nil {
  		return err
  	}
  	if result.Result != "Successfully deleted all new_thread's CTAs" {
  		return fmt.Errorf("Error occured while deleting get started button, invalid result: %s", result.Result)
  	}
  	return nil
  }
docs: // DeleteGetStartedButton delets a button set by SetGetStartedButton