Update arrays.js

Author: angelo983

lib/web/mage/utils/arrays.js

@@ -101,7 +101,7 @@ define([
                 newIndex,
                 target;
 
-            if (typeof position === 'undefined') {
+            if (typeof position === 'undefined' || position == null) {
                 position = -1;
             } else if (typeof position === 'string') {
                 position = isNaN(+position) ? position : +position;