Index.php

<?php
/**
 *
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Cms\Controller\Adminhtml\Wysiwyg\Images;

class Index extends \Magento\Cms\Controller\Adminhtml\Wysiwyg\Images
{
    /**
     * @var \Magento\Framework\View\Result\LayoutFactory
     */
    protected $resultLayoutFactory;

    /**
     * @param \Magento\Backend\App\Action\Context $context
     * @param \Magento\Framework\Registry $coreRegistry
     * @param \Magento\Framework\View\Result\LayoutFactory $resultLayoutFactory
     */
    public function __construct(
        \Magento\Backend\App\Action\Context $context,
        \Magento\Framework\Registry $coreRegistry,
        \Magento\Framework\View\Result\LayoutFactory $resultLayoutFactory
    ) {
        $this->resultLayoutFactory = $resultLayoutFactory;
        parent::__construct($context, $coreRegistry);
    }

    /**
     * Index action
     *
     * @return \Magento\Framework\Controller\ResultInterface
     */
    public function execute()
    {
        $storeId = (int)$this->getRequest()->getParam('store');

        try {
            $this->_objectManager->get(\Magento\Cms\Helper\Wysiwyg\Images::class)->getCurrentPath();
        } catch (\Exception $e) {
            $this->messageManager->addErrorMessage($e->getMessage());
        }
        $this->_initAction();
        /** @var \Magento\Framework\View\Result\Layout $resultLayout */
        $resultLayout = $this->resultLayoutFactory->create();
        $resultLayout->addHandle('overlay_popup');
        $block = $resultLayout->getLayout()->getBlock('wysiwyg_images.js');
        if ($block) {
            $block->setStoreId($storeId);
        }
        return $resultLayout;
    }
}