feat(export): can export dossier with referentiel values

app/models/types_de_champ/drop_down_list_type_de_champ.rb

@@ -1,6 +1,14 @@
 # frozen_string_literal: true
 
 class TypesDeChamp::DropDownListTypeDeChamp < TypesDeChamp::TypeDeChampBase
+  def champ_value_for_export(champ, path = :value)
+    if referentiel? && path != :value
+      champ.referentiel_item_data&.dig(path)
+    else
+      champ.value
+    end
+  end
+
   def columns(procedure:, displayable: true, prefix: nil)
     if referentiel?
       referentiel.headers.map do |header|
@@ -18,4 +26,21 @@ def columns(procedure:, displayable: true, prefix: nil)
       super
     end
   end
+
+  def paths
+    paths = []
+    if referentiel?
+      referentiel.headers.each do |header|
+        paths.push({
+          libelle: "#{libelle} (#{header})",
+          description: "#{description} (#{header})",
+          path: header.parameterize.underscore,
+          maybe_null: public? && !mandatory?
+        })
+      end
+      paths
+    else
+      super
+    end
+  end
 end