[FIX] portal: cast type to consteq signed token

To post a comment with a signed token, we compare tokens with the pid.
The token is signed with the pid, which is an integer. When checking
access, we compare the token with a pid as char. Obviously, the comparison
failed, and posting the message is refused, as the 2 'pid' does not
share the same type.
This commit cast the recieved 'pid' into an integer before checking
special access.

closes odoo/odoo#30906

addons/portal/controllers/mail.py

@@ -53,7 +53,8 @@ def _message_post_helper(res_model, res_id, message, token='', nosubscribe=True,
     record = request.env[res_model].browse(res_id)
 
     # check if user can post
-    if _check_special_access(res_model, res_id, token=token, _hash=kw.get('hash'), pid=kw.get('pid')):
+    pid = int(kw['pid']) if kw.get('pid') else False
+    if _check_special_access(res_model, res_id, token=token, _hash=kw.get('hash'), pid=pid):
         record = record.sudo()
     else:
         raise Forbidden()