How do I get Posts List block to show my custom post type?

I'm working on a small plugin that uses a custom post type. I would like to create a page that lists all posts of that type. The Posts List block's description states that plugins may add more post types to its filter, but I found no documentation on how to do that:

    register_post_type('test_post_type', array(
        'labels' => array(
            'name'          => __('Test Posts'),
            'singular_name' => __('Test Post'),
        ),
        'public'       => true,
        'publicly_queryable' => true,
        'rewrite'      => array('slug' => 'webhook_post'),
        'show_ui'      => true,
        'has_archive'  => false,
        'supports'     => array('title', 'editor', 'author', 'thumbnail', 'excerpt', 'comments'),
        'show_in_rest' => true,
    ));

https://preview.redd.it/cvf8qh2t83gd1.png?width=275&format=png&auto=webp&s=2b8cfc02a1d4d3babc8849f0e414946c90ccd72d

Under Post Type, only Post and Page are listed. How do I add my custom type?