lib: fix validateport error message when allowZero is false

PR-URL: https://github.com/nodejs/node/pull/32861
Fixes: https://github.com/nodejs/node/issues/32857


Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>