MC-4126: Duplicate row border after switching Row appearance

- Revert changes made in b5d921b

Author: davemacaulay

app/code/Magento/PageBuilder/view/adminhtml/web/js/unit/object-assign-polyfill.js

@@ -7,7 +7,6 @@
 /* jscs:disable requireCamelCaseOrUpperCaseIdentifiers */
 define([
     'jquery',
-    'Magento_PageBuilder/js/unit/object-assign-polyfill',
     'Magento_PageBuilder/js/content-type/block/mass-converter/widget-directive'
 ], function ($, polyfill, WidgetDirective) {
     'use strict';

dev/tests/js/jasmine/tests/app/code/Magento/PageBuilder/view/adminhtml/web/js/content-type/block/mass-converter/widget-directive.test.js

@@ -7,7 +7,6 @@
 /* jscs:disable requireCamelCaseOrUpperCaseIdentifiers */
 define([
     'jquery',
-    'Magento_PageBuilder/js/unit/object-assign-polyfill',
     'Magento_PageBuilder/js/content-type/products/mass-converter/widget-directive'
 ], function ($, polyfill, WidgetDirective) {
     'use strict';