When adding new HTTPS listener using the Web Console, user is not able to do so without specifying ssl-context attribute which is not marked as required despite that it is.

Following is the output from CLI:

/subsystem=undertow/server=default-server/https-listener=aaa:add(socket-binding=management-https)
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0172: ssl-context is required",
    "rolled-back" => true
}

Steps to reproduce:
1. Go to the HTTP server configuration page via Subsystem -> Web/HTTP - Undertow -> HTTP -> HTTP Server tab
2. Click 'View' on any of your servers
3. Click 'HTTPS Listener' tab -> 'Add'
4. Fill in attributes marked as required and click 'Save'