Incorrect name of Selected Shipping Method

[naydav]

The easier way to reproduce a bug is adding assert to current API-functional tests

\Magento\GraphQl\Ups\SetUpsShippingMethodsOnCartTest

public function testSetUpsShippingMethod(string $methodCode, string $methodTitle) {
    self::assertEquals($methodTitle, $shippingAddress['selected_shipping_method']['method_title']);
}

Actual result: method title is incorrect ('1GDN')
Expected result: method title is equal to $methodTitle

[atwixfirster]

Pull request: #647

[naydav]

#647