<!-- Please help us process GitHub issues faster by providing the necessary information in the template format that follows. We might not be able to assist with issues which lack important information. --> <!-- Please submit: * Feature requests to our UserVoice Portal at https://goo.gl/HsVr7R. * Support requests to https://www.telerik.com/account/support-tickets. --> It would be helpful if user is able to pass custom message box in ConversationalUi component. <!-- Leave one of the following options. --> * Suggestion for improvement