How to reproduce the bug:
------------------------
- Create a new user
- Log in as that user
- Go to a forum that don't require karma to ask a question.
- Create a new post
- On validation, you'll end up on a 404 page.
If we use the portal user instead, we see the post with a banner explaining
it has to be validated. This should be the result here too.
Specifications:
--------------
- When new users (karma = 0) create a post, redirect them to the page
relating to their question.
task-3372016
closesodoo/odoo#130857
X-original-commit: 9f624795c68d69ddf212657fe43cc45fc32747a0
Signed-off-by: Stéphane Debauche (std) <std@odoo.com>