Filter - Change admin-ajax.php upload URL

 add_filter('dnd_cf7_ajax_url', function(){
    return trailingslashit( site_url() ) . '?ajax-dnd-upload=true';
 });

 add_action( 'init', function() {
    if ( isset( $_GET['ajax-dnd-upload'] ) && 'true' === $_GET['ajax-dnd-upload'] ) {
        if ( ! empty( $_REQUEST['action'] ) && is_scalar( $_REQUEST['action'] ) ) {
            if ( has_action( 'wp_ajax_' . $_REQUEST['action'] ) ) {
                do_action( 'wp_ajax_' . $_REQUEST['action'] );
            }
        }
        die('0');
    }
 });