We have a lot of hits without any forum_origin which will raise an
error 500 because this parameter is required. But because this params is
not into the controller but received as a get parameter, it will match
the controller and return an error 500 instead of a beautiful 404.
Some controller like 'open_partner' redirect to this url without the
parameter forum_origin too, leading in a 500 in all cases.
Better for uX to have this param, but not critical to display the page.
The only negative impact will be to have a 'Back' button that return to
this new default value '/forum'.
closesodoo/odoo#114461
X-original-commit: 991d1c430f2c9bb0d2b2d7ac8f75338eafd2aced
Signed-off-by: Jérémy Kersten <jke@odoo.com>