erp5_free_subscription: Add missing property sheet reference on Free Subscription Request

bt5/erp5_free_subscription/PortalTypePropertySheetTemplateItem/property_sheet_list.xml

@@ -8,5 +8,6 @@
   <item>DublinCore</item>
   <item>Reference</item>
   <item>Person</item>
+  <item>Reference</item>
  </portal_type>
 </property_sheet_list>
\ No newline at end of file

bt5/erp5_free_subscription/bt/template_portal_type_property_sheet_list

@@ -2,5 +2,6 @@ Free Subscription Request | Arrow
 Free Subscription Request | DublinCore
 Free Subscription Request | Reference
 Free Subscription Request | Person
+Free Subscription Request | Reference
 Free Subscription | DublinCore
 Free Subscription | Version
\ No newline at end of file