make Gutenberg Galleries link to Media File by default

functions.php

// make galleries link to Media File
// https://wordpress.stackexchange.com/questions/115368/overide-gallery-default-link-to-settings
function make_galleries_link_to_file() {
    $post_type_object = get_post_type_object( 'post' );
    $post_type_object->template = array(
        array( 'core/gallery', array(
            'linkTo' => 'media',
        ) ),
    );
}
add_action( 'init', 'make_galleries_link_to_file' );