SUPESC-521 Fixed adding length attribute to product (#9331)

SUPESC-521 Fixed adding `length` attribute to product

Author: andrew-maslov

assets/Zed/js/modules/product-attribute.js

@@ -174,7 +174,9 @@ function AttributeManager() {
     };
 
     _attributeManager.resetRemovedKey = function (key) {
-        delete _attributeManager.removedKeys[key];
+        _attributeManager.removedKeys = _attributeManager.removedKeys.filter(function (removedKey) {
+            return removedKey !== key;
+        });
     };
 
     _attributeManager.resetRemovedKeysCache = function () {