MC-4459: Convert OnePageCheckoutOfflinePaymentMethodsTest to MFTF

- Remove duplicate element

Author: tomreece

app/code/Magento/Checkout/Test/Mftf/Section/CheckoutPaymentSection.xml

@@ -25,7 +25,6 @@
         <element name="guestRegion" type="select" selector=".billing-address-form select[name*='region_id']"/>
         <element name="guestPostcode" type="input" selector=".billing-address-form input[name*='postcode']"/>
         <element name="guestTelephone" type="input" selector=".billing-address-form input[name*='telephone']"/>
-        <element name="guestCountry" type="select" selector=".billing-address-form select[name*='country_id']"/>
         <element name="billingAddress" type="text" selector=".payment-method._active div.billing-address-details"/>
         <element name="cartItems" type="text" selector="ol.minicart-items"/>
         <element name="cartItemsArea" type="button" selector="div.block.items-in-cart"/>