[FIX] mail: effectively allow to post when notified on unreachable documents

When being notified on a document they cannot read users should be able to
post, as indicated in message ACLs. However some data preparation prevents
from doing it as ACLs are raised on document level.

In this commit we sudo the call to display_name to populate record_name when
not given. Indeed access is checked at message level so no need to crash in
this specific use case.

Task-3213982 (Mail: fix 'multi-company' post support)

X-original-commit: odoo/odoo@2d73c61136
Part-of: odoo/odoo#114511

addons/mail/models/mail_thread.py

@@ -2011,7 +2011,9 @@ class MailThread(models.AbstractModel):
         if 'email_add_signature' not in msg_values:
             msg_values['email_add_signature'] = True
         if not msg_values.get('record_name'):
-            msg_values['record_name'] = self.display_name
+            # use sudo as record access is not always granted (notably when replying
+            # a notification) -> final check is done at message creation level
+            msg_values['record_name'] = self.sudo().display_name
         msg_values.update({
             # author
             'author_id': author_id,