[FIX] l10n_ch: don't assume the bank account of the company always has a currency_id

Since this field is not required on res.partner.bank (which is fine: we want it to be synchronized with the journal's currency, which is None if the journal uses company currency), the parameter received by validate_swiss_code_arguments ended out being an empty recordset in case the company was directly in CHF. This caused the QR code to never be displayed in this situation.

closes odoo/odoo#43282

Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>

addons/l10n_ch/models/res_bank.py

@@ -123,9 +123,8 @@ class ResPartnerBank(models.Model):
         qr_code_url = '/report/barcode/?type=%s&value=%s&width=%s&height=%s&humanreadable=1' % ('QR', werkzeug.url_quote_plus(qr_code_string), 256, 256)
         return qr_code_url
 
-    @api.model
     def validate_swiss_code_arguments(self, currency, debitor):
-
+        currency = currency or self.company_id.currency_id
         t_street_comp = '%s %s' % (self.company_id.street if (self.company_id.street != False) else '', self.company_id.street2 if (self.company_id.street2 != False) else '')
         t_street_deb = '%s %s' % (debitor.street if (debitor.street != False) else '', debitor.street2 if (debitor.street2 != False) else '')
         number = self.find_number(t_street_comp)