dgram: use simplified validator

The `dgram` lib module should use the simplified `validatePort()`
validator.

PR-URL: https://github.com/nodejs/node/pull/39753


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Zijian Liu <lxxyxzj@gmail.com>