File/image input field does not work when in group

Hello,

I took your image field demo and put it in a group. The image upload does not work anymore.

Can you fix this ?

Regards,

    $meta_boxes[] = array(
        'post_types' => array( 'post' ),
        'title'  => esc_html__( 'Image Upload Demo', 'your-prefix' ),
        'fields' => array(
            array(
                'name'    => '',
                'id'      => 'test_group',
                'type'    => 'group',
                'fields' => array(
                    array(
                        'id'               => 'image',
                        'name'             => esc_html__( 'Image', 'your-prefix' ),
                        'type'             => 'image',
                        'force_delete'     => false,
                        'max_file_uploads' => 2,
                    ),
                ),
            ),
        ),
    );