Use public REST URL prefix in 'ontology already exists' 409 error

The 409 error returned when creating an ontology with an existing acronym
interpolated ont.id directly, exposing the internal id_url_prefix
(http://data.bioontology.org/) instead of the portal's public URL.

Run the id through Base.replace_url_id_to_prefix so the message reports
the configured rest_url_prefix, matching normal serialized output.

Author: maboukerfa

controllers/ontologies_controller.rb

@@ -182,7 +182,7 @@ def create_ontology
         ont = instance_from_params(Ontology, params)
       else
         error_msg = <<-ERR
-        Ontology already exists, see #{ont.id}
+        Ontology already exists, see #{LinkedData::Models::Base.replace_url_id_to_prefix(ont.id)}
         To add a new submission, POST to: /ontologies/#{params['acronym']}/submission.
         To modify the resource, use PATCH.
         ERR