Changes to Get the iCal file for all published group open events and events for which a member has registered. Roles: public.

added the optional property error/errorId to the response with the 400 status

added the optional property error/errorId to the response with the 401 status

added the optional property error/errorId to the response with the 403 status

added the optional property error/errorId to the response with the 404 status

added the optional property error/errorId to the response with the 500 status