[fix #1066] Fix links to related dossier for experts

- link to full dossier if gestionnaire is affected on procedure
- link to avis if avis expert requested on related dossier

app/helpers/dossier_link_helper.rb

@@ -0,0 +1,12 @@
+module DossierLinkHelper
+  def dossier_linked_path(gestionnaire, dossier)
+    if dossier.procedure.gestionnaires.include?(gestionnaire)
+      dossier_path(dossier.procedure, dossier)
+    else
+      avis = dossier.avis.find_by(gestionnaire: gestionnaire)
+      if avis.present?
+        avis_path(avis)
+      end
+    end
+  end
+end