When validating postcode exit early in the update function if the 'op…

…tion' is undefined. This can happen with stores that have a different deault country than US

app/code/Magento/Ui/view/base/web/js/form/element/region.js

@@ -35,6 +35,11 @@ define([
                 return;
             }
             option = options[value];
+
+            if (typeof option === 'undefined') {
+                return;
+            }
+
             defaultPostCodeResolver.setUseDefaultPostCode(!option['is_zipcode_optional']);
 
             if (this.skipValidation) {