It seems like that is no way to translate this day suffix for other language if using PHP datetime format, you can read their PHP documentation http://php.net/manual/en/function.date.php (screenshot : https://take.ms/ODf83)

This is the datetime format we use to translate this :

COM_EASYSOCIAL_VIDEOS_DATE_FORMAT="jS F Y"

Since that is no way to translate this, you can override this language constant on your site to remove this day suffix.

Replace with

COM_EASYSOCIAL_VIDEOS_DATE_FORMAT="j F Y"