erp5_crm: allow Embedded Files in Letters

bt5/erp5_crm/PortalTypeAllowedContentTypeTemplateItem/allowed_content_types.xml

@@ -18,6 +18,9 @@
   <item>Visit</item>
   <item>Web Message</item>
  </portal_type>
+ <portal_type id="Letter">
+  <item>Embedded File</item>
+ </portal_type>
  <portal_type id="Mail Message">
   <item>Embedded File</item>
  </portal_type>

bt5/erp5_crm/bt/template_portal_type_allowed_content_type_list

@@ -11,6 +11,7 @@ Event Module | Short Message
 Event Module | Site Message
 Event Module | Visit
 Event Module | Web Message
+Letter | Embedded File
 Mail Message | Embedded File
 Meeting Module | Meeting
 Meeting | Event Path