small bug fix on woocommerce checkout URL for PayPal plugin

I have a paypal plugin installed for woocommerce which has a bug as we run a multilingual site with wpml. In the checkout, when choosing PayPal to pay and trying to click on place order, it redirects to xxx/wc-api/Express_Checkout_Gateway/?action=ex_set_express_checkout which works fine. But when the checkout page is in any other language other than the main language, for example german, the plugin redirects xxx/de/wc-api/Express_Checkout_Gateway/?action=ex_set_express_checkout , so it adds the language directory to the url which breaks the redirect to PayPal. So you have to edit this in the PayPal plugin, so it always goes to /wc-api/Express_Checkout_Gateway/?action=ex_set_express_checkout in every language.