Don't use canonical path for group children

config/routes/group.rb

@@ -41,9 +41,6 @@ scope(path: 'groups/*id',
   get :merge_requests, as: :merge_requests_group
   get :projects, as: :projects_group
   get :activity, as: :activity_group
-  scope(path: '-') do
-    get :children, as: :group_children
-  end
   get '/', action: :show, as: :group_canonical
 end
 
@@ -56,5 +53,9 @@ constraints(GroupUrlConstrainer.new) do
     patch '/', action: :update
     put '/', action: :update
     delete '/', action: :destroy
+
+    scope(path: '-') do
+      get :children
+    end
   end
 end