Admin UI doesn't add the necessary REQUEST parameter

[jacobwod]

When adding a search or edit service from a QGIS server we have to add ?SERVICE=WFS to the URL in order to be able to show attributes in admin. If we add the service parameter the service seems to work but calls from the edit service adds a second service parameter. In order to have the same format of URL for layer, search and edit it would be nice to not have to add the service parameter.

Originally posted by @WCarlsson in #907 (comment)