[FIX] website: not rely on sudo cache magic for menu visibility

Before this commit conditions based on `_handle_visibility` and
`_get_cached_visibility` did work only by relying on the cache of the
`menu.page_id` being populated when accessing `is_visible` in sudo.
This does not work if the cache is cleared between the calls.

This commit makes sure all 3 conditions have access the record.

The actual issue has not been reproduced locally yet.
The various workers, crons, websocket work on distinct envs - even
through code they cannot impact the cache of another local env outside
the `check_signaling` system which is only used between requests.
For the problem to occur, some intra-request multithreading is needed
but it could not be located so far.

task-3149270

closes odoo/odoo#111217

Signed-off-by: Romain Derie (rde) <rde@odoo.com>

addons/website/models/website_menu.py

@@ -115,11 +115,12 @@ class Menu(models.Model):
     def _compute_visible(self):
         for menu in self:
             visible = True
-            if menu.page_id and not menu.user_has_groups('base.group_user') and \
-                (not menu.page_id.sudo().is_visible or
-                 (not menu.page_id.view_id._handle_visibility(do_raise=False) and
-                 menu.page_id.view_id.visibility != "password")):
-                visible = False
+            if menu.page_id and not menu.user_has_groups('base.group_user'):
+                page_sudo = menu.page_id.sudo()
+                if (not page_sudo.is_visible
+                    or (not page_sudo.view_id._handle_visibility(do_raise=False)
+                        and page_sudo.view_id.visibility != "password")):
+                    visible = False
             menu.is_visible = visible
 
     @api.model