[FIX] l10n_fr_pos_cert: import `api`

Following forward-port.

addons/l10n_fr_pos_cert/models/account_bank_statement.py

 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
-from odoo import models
+from odoo import models, api
 from odoo.tools.translate import _
 from odoo.exceptions import UserError