[FIX] website: language must be empty if company has no website

The `language_ids` field on `res.config.settings` was made required field.
However, in a multi-company setting, where the active company does not have a
website, this field will be empty, and the user won't be able to save
any configuration changes.

closes odoo/odoo#41027

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

addons/website/models/res_config_settings.py

@@ -18,7 +18,7 @@ class ResConfigSettings(models.TransientModel):
     website_domain = fields.Char('Website Domain', related='website_id.domain', readonly=False)
     website_country_group_ids = fields.Many2many(related='website_id.country_group_ids', readonly=False)
     website_company_id = fields.Many2one(related='website_id.company_id', string='Website Company', readonly=False)
-    language_ids = fields.Many2many(related='website_id.language_ids', relation='res.lang', readonly=False, required=True)
+    language_ids = fields.Many2many(related='website_id.language_ids', relation='res.lang', readonly=False)
     language_count = fields.Integer(string='Number of languages', compute='_compute_language_count', readonly=True)
     website_default_lang_id = fields.Many2one(
         string='Default language', related='website_id.default_lang_id', readonly=False,