Remove unnecessary include

Since `Project` includes `GitlabRoutingHelper`, which then includes
`EE::GitlabRoutingHelper`, there's no need for to include
`EE::GitlabRoutingHelper` in `EE::Project`.

ee/app/models/ee/project.rb

@@ -843,5 +843,3 @@ module EE
     end
   end
 end
-
-EE::Project.include_if_ee('::EE::GitlabRoutingHelper')