refs #756: fix PaymentMethod::getCurrentPaymentAmount (#757)
refs #756: fix PaymentMethod::getCurrentPaymentAmount (#757)

* refs #756: fix PaymentMethod::getCurrentPaymentAmount

* fix typo

* refs #756: implemente CR feedback

* Update Helper/PaymentMethods.php

* Update Helper/PaymentMethods.php

Co-authored-by: Attila Kiss <cb52694b1647fc30263fd3b621b5b907499f8e72@users.noreply.github.com>
Co-authored-by: Alexandros Moraitis <e3aeed8f14c36d37f6382641b0d27c8a6dc8e4a3@adyen.com>
Adyen/adyen-magento2,Adyen/adyen-magento2,Adyen/adyen-magento2