magento-test/app/code/Magento/GroupedImportExport/etc/di.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\CatalogImportExport\Model\Export\RowCustomizer\Composite">
        <arguments>
            <argument name="customizers" xsi:type="array">
                <item name="groupedProduct" xsi:type="string">Magento\GroupedImportExport\Model\Export\RowCustomizer</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\CatalogImportExport\Model\StockItemImporterInterface">
        <plugin name="update_grouped_product_stock_status_plugin" type="Magento\GroupedImportExport\Plugin\CatalogImportExport\Model\StockItemImporter\UpdateGroupedProductStockStatusPlugin" />
    </type>
</config>