Since https://github.com/odoo/odoo/pull/126713, deleting a message would crash as the `mail/message/update_content` route is called without passing the `partner_ids` parameter. This commit fixes the issue by making the parameter optional. closes odoo/odoo#127284 X-original-commit: 34abd3dc1d159962a376b248134d0cd4977f3dcb Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>