[Bug] Duplication of payments once someone will decide to resign from PayPal as payment method

[lchrusciel]

SyliusPayPalPlugin version affected: ^1.5.x

Description
When during checkout we will select PayPal payment method and then move back the main website, the payment duplicates.

Taking a look at admin panel, suggest that by accident we are creating two new payments - one in state new and another one in state cart

Which can be related to the two payments visible on the first screen. I'm surprised that cart payment is visible both in admin and in the payment selection view, but it is still more probable than showing cancelled payment in the shop.

Steps to reproduce

1. Add something to cart
2. Address cart
3. Select any shipping method
4. Select "PayPal" payment method
5. Complete checkout
6. Few seconds wait may be needed here
7. Click move back button on the left top corner
8. See two payments

Possible Solution