[FIX] account_payment: send amount in right currency

While sending payment request to acquirer
the amount used was the amout_residual_signed

This amound is in the currency of the company
and may be negative.

The currency send to the acquirer is the
currency on the invoice so you expect the
amount to be in the same currency and
being positive

amount_residual is exactly that amount

Solution: user amount_residual
          instead of amount_residual_signed

closes odoo#46039

Signed-off-by: Laurent Smet <[email protected]>

addons/account_payment/models/payment.py

@@ -20,7 +20,7 @@ def render_invoice_button(self, invoice, submit_txt=None, render_values=None):
             values.update(render_values)
         return self.acquirer_id.with_context(submit_class='btn btn-primary', submit_txt=submit_txt or _('Pay Now')).sudo().render(
             self.reference,
-            invoice.amount_residual_signed,
+            invoice.amount_residual,
             invoice.currency_id.id,
             values=values,
         )