Fixed syntax errors caused by new less.php version

Author: vovayatsyuk

app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_shipping.less

@@ -32,7 +32,7 @@
 @checkout-shipping-item-mobile__active__padding: 15px (@indent__l + 5px) 15px 18px;
 
 @checkout-shipping-item-before__border-color: @color-gray80;
-@checkout-shipping-item-before__height: calc(~'100% - 20px');
+@checkout-shipping-item-before__height: ~"calc(100% - 20px)";
 
 @checkout-shipping-method__border: @checkout-step-title__border;
 @checkout-shipping-method__padding: @indent__base;

app/design/frontend/Magento/luma/Magento_Checkout/web/css/source/module/checkout/_shipping.less

@@ -32,7 +32,7 @@
 @checkout-shipping-item-mobile__active__padding: 15px (@indent__l + 5px) 15px 18px;
 
 @checkout-shipping-item-before__border-color: @color-gray80;
-@checkout-shipping-item-before__height: calc(~'100% - 20px');
+@checkout-shipping-item-before__height: ~"calc(100% - 20px)";
 
 @checkout-shipping-method__border: @checkout-step-title__border;
 @checkout-shipping-method__padding: @indent__base;