* fix traceback when vat is not defined, return directly 0. * remove api.model * add ensure_one() to avoid misuse of the method closes odoo/odoo#84952 X-original-commit: 5cd4df745462fcc12b9d92def9cf903ebd0df143 Related: odoo/enterprise#24565 Signed-off-by: Josse Colpaert <jco@odoo.com>