Removing custom sort order from admin page listing

By default pages are order by menu_order then title.
When you are adding filter country you are ordering them by meta_value

There are two options

1. Remove everything that you added country and orderby pages will be back to default order.
2. If you can not remove orderby but can remove country then adjust your code in this way and order pages again by menu_order title only when country is not set and orderby is type.

Updated code:-

function type_column_orderby($vars) {
    // You can also wrap this code in one more condition using $vars to only alter page list!
    if (!empty($_GET['country']) && isset($vars['orderby']) && 'type' == $vars['orderby']) {
        $vars = array_merge( $vars, array(
            'meta_key' => 'type',
            'orderby' => 'meta_value'
        ));
    } else if (empty($_GET['country']) && isset($vars['orderby']) && 'type' == $vars['orderby']) {
        $vars = array_merge( $vars, array(
            'orderby' => 'menu_order title',
            'posts_per_page' => -1
        ));
    }
    return $vars;
}

NOTE: request filter effect every query so wrap your filter in
load-edit.php action to only alter the post type listing query.

add_action( 'load-edit.php', 'custom_page_order' );
function custom_page_order() {
    add_filter('request', 'type_column_orderby');
}