[FIX] l10n_es_edi_sii: do not change the success

Before, the 'success' key was removed from the results
of the invoice processing and as such the invoice
was never put as successfully sent, but you sent it
again and again.

closes odoo/odoo#81911

X-original-commit: 853ff30b76a56bcb9af88256aac3a3ceb93bf562
Signed-off-by: Laurent Smet <las@odoo.com>
Signed-off-by: Josse Colpaert <jco@odoo.com>

addons/l10n_es_edi_sii/models/account_edi_format.py

@@ -666,5 +666,5 @@ class AccountEdiFormat(models.Model):
                     'res_model': inv._name,
                     'res_id': inv.id,
                 })
-                res[inv] = {'attachment': attachment}
+                res[inv]['attachment'] = attachment
         return res