[FIX] website_forum: users count requires super-user permissions

Introduced at 893d7fa864
during new API conversion: missing `sudo()`.

Fixes #6578

addons/website_forum/controllers/main.py

@@ -400,7 +400,7 @@ class WebsiteForum(http.Controller):
     def users(self, forum, page=1, **searches):
         User = request.env['res.users']
         step = 30
-        tag_count = User.search_count([('karma', '>', 1), ('website_published', '=', True)])
+        tag_count = User.sudo().search_count([('karma', '>', 1), ('website_published', '=', True)])
         pager = request.website.pager(url="/forum/%s/users" % slug(forum), total=tag_count, page=page, step=step, scope=30)
         user_obj = User.sudo().search([('karma', '>', 1), ('website_published', '=', True)], limit=step, offset=pager['offset'], order='karma DESC')
         # put the users in block of 3 to display them as a table