3493006: Fix Argument #1 url must be of type string, Drupal\Core\Url given

I encountered this issue after adding a product variation to the cart, it happens when redirecting to see the product variant details, for example /shopify/redirect?variant_id=00000000000000, the following error appears in the URL in question and in the Recent log messages Argument #1 ($url) must be of type string, Drupal\Core\Url given, called in shopify/src/Controller/ShopifyRedirect.php on line 30 in Symfony\Component\HttpFoundation\RedirectResponse->__construct(). The proposed solution is to call the toString() function after calling the toUrl() function to transform the Drupal\Core\Url class object into a string with the url.