Add an option to disable 'dismissAction'

[roalexan]

Right now there is the ability to customize the text for the "feedback action" via

{
  /** Text to show on button that allows user to hide/ignore the feedback request. Default value is `'dismiss'` */
  dismissAction?: FeedbackAction
}

It seems to me that some bot framework developers might not want to show this button at all, since users can also ignore feedback by just not clicking any of the buttons and continuing their conversation. This might be a slightly simpler interface (one less button) that we want to enable for our bot framework developers.

BTW, I tried setting the text as an empty string, but it then resorts to the default ("dismiss").