module: fix check for package.json at volume root

Fix package.json files at the volume root so that
when they contain {"type": "module"}, they behave
as documented, like such a package.json file in
any other folder.

Fixes: https://github.com/nodejs/node/issues/33438

PR-URL: https://github.com/nodejs/node/pull/33476


Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>