[FIX] pos_mercury: set the paid amount to what is authorized by Mercury

Mercury can partially approve transactions in case a card does not
have enough credit available to cover the full amount.

Before this the payment amount was kept as the full purchase amount
leading to a difference between what Mercury charged and what Odoo
registered as charged.

opw-1840946

addons/pos_mercury/static/src/js/pos_mercury.js

@@ -440,6 +440,7 @@ PaymentScreenWidget.include({
                     order.selected_paymentline.paid = true;
                     order.selected_paymentline.mercury_swipe_pending = false;
                     order.selected_paymentline.mercury_amount = response.authorize;
+                    order.selected_paymentline.set_amount(response.authorize);
                     order.selected_paymentline.mercury_card_number = decodedMagtek['number'];
                     order.selected_paymentline.mercury_card_brand = response.card_type;
                     order.selected_paymentline.mercury_card_owner_name = decodedMagtek['name'];