Forwarding the extra query param to the external IdP

I want to forward an extra query param to the external IdP.
I have used the option Forwarded Query Parameters in the IdP configuration but it is not putting the query params in the URL.

I want to add the launch param to the authorized request.
I used by

  1. Setting launch to my URL e.g.http://localhost:8080/?launch=abc and set launch in the Forwarded Query Parameters
  2. using the URL as the http://localhost:8080 and setting launch=abc in the Forwarded Query Parameters
    both of these approaches didn’t work to forward the launch param to the authorize URL.