erp5_crm: Embedded File is required as Allowed Content on Mail Message

   Since the MailMessage_send uses Embeeded File to create attachments, on the Mail Message before send it is required to add it as Allowed Content type, otherwise, it will raise, "ValueError: Disallowed subobject type: Embedded File on <Temporary Mail Message at /erp5/None>"

bt5/erp5_crm/PortalTypeAllowedContentTypeTemplateItem/allowed_content_types.xml

@@ -21,6 +21,9 @@
  <portal_type id="Letter">
   <item>Embedded File</item>
  </portal_type>
+ <portal_type id="Mail Message">
+  <item>Embedded File</item>
+ </portal_type>
  <portal_type id="Meeting">
   <item>Event Path</item>
  </portal_type>

bt5/erp5_crm/bt/template_portal_type_allowed_content_type_list

@@ -12,6 +12,7 @@ Event Module | Site Message
 Event Module | Visit
 Event Module | Web Message
 Letter | Embedded File
+Mail Message | Embedded File
 Meeting Module | Meeting
 Meeting | Event Path
 Preference | Support Request