[FIX] website_forum: wrong user displayed on forum

The function to convert an answer to a comment was creating a new
message with the create_uid of the current user instead of the original
poster, therefore creating a mismatch between the create_uid and the
user of the message author.

Since the template 'website_forum.author_box' was designed to work with
different objects (mail.message & forum.post), it displays the
information of the object.create_uid which is not the correct user in
this case.

This commit ensures that we create the message with the correct user to
avoid the mismatch.

closes odoo/odoo#46486

X-original-commit: 20800955257c4f871cc21f8e21cd22c1a3b0fe9f
Signed-off-by: Toufik Benjaa (tbe) <tbe@odoo.com>

addons/website_forum/models/forum.py

@@ -720,7 +720,8 @@ class Post(models.Model):
             'subtype_xmlid': 'mail.mt_comment',
             'date': self.create_date,
         }
-        new_message = question.with_context(mail_create_nosubscribe=True).message_post(**values)
+        # done with the author user to have create_uid correctly set
+        new_message = question.with_user(self_sudo.create_uid.id).with_context(mail_create_nosubscribe=True).message_post(**values)
 
         # unlink the original answer, using SUPERUSER_ID to avoid karma issues
         self.sudo().unlink()