prevent breaking smartd service with extra options

PR: https://github.com/truenas/middleware/pull/10421

Seen in the wild. Someone had put `-d nvme` as an extra smart option in our API. Surprisingly, we do 0 validation here. We statically generate the smartd config and don't "overwrite" the config with any of these flags so it's best to prevent them here to prevent the smartd.conf from being generated incorrectly which ultimately prevents the smartd service from starting.