[FIX] point_of_sale: random error when running PaymentScreenTotalDueWithOverPayment

PaymentScreenTotalDueWithOverPayment result to random runbot error because the
test is performing a series of steps that clicks the validate button which will
randomly result to going to the ReceiptScreen which is not the goal of the test.

In this commit, we replace the use of `pay` method with a more granular series
of steps to make sure that the test doesn't click the validate button and will
properly make the succeeding checks on the amounts in the PaymentScreen.

closes odoo/odoo#117501

Signed-off-by: Joseph Caburnay (jcb) <jcb@odoo.com>

addons/point_of_sale/static/tests/tours/PaymentScreen.tour.js

@@ -195,12 +195,12 @@ odoo.define('point_of_sale.tour.PaymentScreen', function (require) {
     ProductScreen.do.clickPayButton();
 
     PaymentScreen.check.totalIs('1.95');
-    PaymentScreen.exec.pay('Cash', '5');
+    PaymentScreen.do.clickPaymentMethod('Cash');
+    PaymentScreen.do.pressNumpad('5');
 
     PaymentScreen.check.remainingIs('0.0');
     PaymentScreen.check.changeIs('3.05');
     PaymentScreen.check.totalDueIs('1.95');
-    Chrome.do.clickTicketButton();
 
     Tour.register('PaymentScreenTotalDueWithOverPayment', { test: true, url: '/pos/ui' }, getSteps());