cnspec does not report check-in to upstream as one might expect

[czunker]

Describe the bug
In the platform, we show a "Last Check-in" for managed clients. But this does not get updated when a scan happens or the service is restarted.

From the cnspec service logs:

Oct 26 06:38:56 ubuntu-jammy cnspec[8606]: → next scan in 1h0m40.42483421s
Oct 26 07:39:36 ubuntu-jammy cnspec[8606]: → discover related assets for 1 asset(s)
Oct 26 07:39:36 ubuntu-jammy cnspec[8606]: → synchronize assets
Oct 26 07:40:23 ubuntu-jammy crontab[9836]: (root) LIST (root)
Oct 26 07:40:26 ubuntu-jammy cnspec[8606]: → scan for asset ubuntu-jammy (Ubuntu 22.04.1 LTS) completed
Oct 26 07:40:26 ubuntu-jammy cnspec[8606]: → next scan in 1h20m15.867470213s

But in the UI:

To Reproduce
Steps to reproduce the behavior:

1. Create a Ubuntu VM
2. Create a workstation integration in the UI
3. Install the client in the VM as suggested by the UI
4. See the client report in the UI
5. Wait some time and see scans happening
6. Note that the UI does not show an updated "Last Check-in"

Expected behavior
I'd expect the client to check-in with a scan.

Desktop (please complete the following information):

• OS: Ubuntu 22.04 VM, but also reported on Windows
• cnspec 9.3.3

Additional context
I've not checked the code so far, whether we have an interval set or something like that.
Perhaps we automatically check-in every 24 hours?

[czunker]

This leads to wired data. The managed client shows as missing:

But the assets shows a recent scan:

[czunker]

Also calling status, does not change the managed client data:

cnspec status
→ loaded configuration from /home/vagrant/.config/mondoo/mondoo.yml using source default
→ Platform:	ubuntu
→ Version:	22.04
→ Hostname:	ubuntu-jammy
→ IP:		10.0.2.15
→ Time:		2023-10-27T08:19:53Z
→ Version:	9.3.3 (API Version: 9)
→ API ConnectionConfig:	https://api.edge.mondoo.com
→ API Status:	SERVING
→ API Time:	2023-10-27T08:19:53Z
→ API Version:	9
→ Client:	//agents.api.mondoo.app/spaces/mondoo-k8s/agents/2XI0p17UVv5h6OjxRjHeXUeAV8b
→ Service Account:	//agents.api.mondoo.app/spaces/mondoo-k8s/serviceaccounts/2XI0oy2XKFt9f6rHka3NVPpJOfy
→ client is registered
→ client authenticated successfully

[czunker]

#913 is still needed.