Secondaries get their own URL from config

Not from `geo_nodes.url`.

ee/app/controllers/ee/sessions_controller.rb

@@ -14,7 +14,7 @@ module EE
       return super if signed_in?
 
       if ::Gitlab::Geo.secondary_with_primary?
-        redirect_to oauth_geo_auth_url(host: ::Gitlab::Geo.current_node.url, state: geo_login_state.encode)
+        redirect_to oauth_geo_auth_url(host: GeoNode.current_node_url, state: geo_login_state.encode)
       else
         super
       end

ee/spec/controllers/ee/sessions_controller_spec.rb

@@ -27,7 +27,7 @@ describe SessionsController, :geo do
           redirect_params = CGI.parse(redirect_uri.query)
 
           expect(response).to have_gitlab_http_status(302)
-          expect(response).to redirect_to %r(\A#{primary_node.url}oauth/geo/auth)
+          expect(response).to redirect_to %r(\A#{Gitlab.config.gitlab.url}/oauth/geo/auth)
           expect(redirect_params['state'].first).to end_with(':')
         end
       end