praudit: correct test case

The -n flag specifies that user and group IDs should remain numeric, not
be mapped to names. The golden output for praudit -n, however,
contained user and group names.

Reported by: markj
Reviewed by: markj
Fixes: ba10bfe509dc ("libbsm: honour AU_OFLAG_NORESOLVE")
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D47434