[FIX] l10n_ar: Properly compute fiscal position for Argentinian

companies.

We revert the change we apply in order to let the user to define their
own fiscal positions, now the fiscal position will be set depending on
the afip responsability.

With this change we fix the error that the fiscal position is properly
setted for the customers that are of type "Responsable Inscription" and
"Consumidor Final".

Before this change the "Compras / Ventas en el Exterior" fiscal position
was wrongly seted, now the fiscal position is leave empty so the related
invoice taxes are properly matched

closes odoo/odoo#38830

X-original-commit: 74f172041351e03f60b1aff0f0eb925e896cd1fa
Signed-off-by: Josse Colpaert <jco@openerp.com>

addons/l10n_ar/models/account_fiscal_position.py

@@ -22,9 +22,7 @@ class AccountFiscalPosition(models.Model):
             ]
             if self.env.context.get('force_company'):
                 domain.append(('company_id', '=', self.env.context.get('force_company')))
-            fp = self.search(domain, limit=1).id
-            if fp:
-                return fp
+            return self.search(domain, limit=1).id
         return super().get_fiscal_position(partner_id, delivery_id=delivery_id)
 
     @api.onchange('l10n_ar_afip_responsibility_type_ids', 'country_group_id', 'country_id', 'zip_from', 'zip_to')