[#5421] Add Assign Deliverable to Issue permission for the new/edit issue form

app/views/issues/_edit_deliverable.html.erb

@@ -1,4 +1,4 @@
-<% if project.module_enabled?(:contracts) %>
+<% if project.module_enabled?(:contracts) && User.current.allowed_to?(:assign_deliverable_to_issue, project) %>
   <p>
     <% options = project.contracts.inject([]) {|data, contract|
          data << [contract.name, contract.deliverables.collect {|d| [d.title, d.id]} ]