[FIX] website: clear cache when menu group is changed

Otherwise, `_get_menu_ids()` won't be recomputed, meaning removing a group from
a menu won't make it appear for restricted user, and adding a group on a menu
won't hide that menu, until a clear cache occurs.

Introduced with 02e01dce516

closes odoo/odoo#48065

X-original-commit: 0131e6d9103f68950ee23c6b0ef1af972370416e
Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>
Signed-off-by: Romain Derie <rdeodoo@users.noreply.github.com>

addons/website/models/website_menu.py

@@ -94,7 +94,7 @@ class Menu(models.Model):
 
     def write(self, values):
         res = super().write(values)
-        if 'website_id' in values:
+        if 'website_id' in values or 'group_ids' in values:
             self.clear_caches()
         return res