Hi Samo,
That field does not support shortcodes unfortunately, for the reason that most shortcodes probably would not work correclty in that scope.
If adding a shortcode there is avoidable, I would rather recommend using regular HTML there, maybe putting a link to a page with the contact form(?).
If the shortcode is needed, the only way to do it is via results templating, and custom coding it there via the PHP version of that shortcode. But once again, even if you placed the form there, it probably would not work correctly – the styling and the functionality of the form would be broken, as usually those are not designed to be used in dynamically loaded content.