[Fleet] API endpoint package_policies returns 500 on PUT with unknown ID

Kibana version: 8.13.4 Elasticsearch version: 8.13.4 Server OS version: Elastic Cloud Browser version: N/A Browser OS version: N/A Original install method (e.g. download page, yum, from source, etc.): N/A

Describe the bug: The package_policies API returns 500 on a PUT request with unknown ID.

Steps to reproduce:

Try to update an integration that doesn't exist:

PUT kbn:/api/fleet/package_policies/noid
{
"id": "noid",
"policy_id": "agentPolicyId",
"package": {
"name": "log",
"version": "1.1.1"
},
"name": "thisisaname",
"description": "",
"namespace": "default",
"inputs": {
"logs-logfile": {
  "enabled": true,
  "streams": {
    "log.log": {
      "enabled": true,
      "vars": {
        "paths": [
          "test"
        ],
        "data_stream.dataset": "generic",
        "tags": [],
        "custom": ""
      }
    }
  }
}
}
}

Watch the request return a 500 server error:

{
"statusCode": 500,
"error": "Internal Server Error",
"message": "An internal server error occurred. Check Kibana server logs for details."
}

Expected behavior: I expect the API to return a 404, just like the agent_policies endpoint:

{
    "statusCode": 404,
    "error": "Not Found",
    "message": "Saved object [ingest-agent-policies/noid] not found"
}

Provide logs and/or server output (if relevant): This is from the kibana logs. Seems like the same message that is returned with the agent_policies 404 response.

...
          "message": "500 Server Error",
          "error": {
            "message": "Saved object [ingest-package-policies/noid] not found"
          },
...

elastic / kibana

[Fleet] API endpoint package_policies returns 500 on PUT with unknown ID #186486