[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 #81902

Signed-off-by: Laurent Smet <las@odoo.com>

addons/l10n_es_edi_sii/models/account_edi_format.py

@@ -672,5 +672,5 @@ def _post_invoice_edi(self, invoices, test_mode=False):
                     'res_model': inv._name,
                     'res_id': inv.id,
                 })
-                res[inv] = {'attachment': attachment}
+                res[inv]['attachment'] = attachment
         return res