How to get the Tags on Publish post hook?

Found Solution :

If there is no data in the request_body, the we can also fetch it from the postID which is already we have.

Changed Code: added condition if data not available, then get it from post id

public static function saveDataInNotificationTable($ID,$request_body)
{
    $post_data = json_decode($request_body);

    $tags = $post_data->tags;

    if($post_data == "" || $post_data == null)
    {
        $tags = get_the_tags($ID);
    }

    if(isset($tags) && is_array($tags) && count($tags) > 0)
    {
       // SOME CODE
    }
}