[inventory] Modify reporting on services per sled agent

[karencfv]

As per #9876 , each sled agent should report on the state of any services that are enabled but not running. This basically means all services in any state other than "online" or "disabled".

$ curl -H "api-version: 25.0.0"  http://[::1]:41139/inventory | jq
<...>
  "smf_services_enabled_not_online": {
    "ok": {
      "services": [
        {
          "fmri": "svc:/site/fake-service4:default",
          "zone": "global",
          "state": "degraded"
        },
        {
          "fmri": "svc:/site/fake-service3:default",
          "zone": "global",
          "state": "offline"
        },
        {
          "fmri": "svc:/site/fake-service:default",
          "zone": "global",
          "state": "maintenance"
        }
      ],
      "errors": [],
      "time_of_status": "2026-03-05T06:54:29.028709437Z"
    }
  },
<...>

DB entries will be added in a follow up PR

[karencfv]

We want this field to be nullable in case the svcs -Za -H -o state,fmri,zone command doesn't actually run for whatever reason. If we were to return an empty vec of services we could just imply that all of the services were healthy when, in fact, we don't actually know.