Integrating coordinator with SSC before integrating with the worker breaks the Tempo cluster

[michaeldmitry]

Bug Description

In the below scenario:
coordinator -> worker
coordinator -> ssc:certificates
The worker eventually comes up after a short time and it has all its needed stuff (config with TLS + certificate with correct hostnames)

For some reason, in some occasions, when the order becomes as follows:
coordinator -> ssc:certificates
coordinator -> worker

The worker gets stuck trying to restart.

To Reproduce

Same as above

Environment

juju: 3.5.4
microk8s: 1.28

Relevant log output

N/A

Additional context

No response

[mmkay]

We've heavily changed how it works. It might be worth to attempt to reproduce this and if it doesn't we can close the issue.

The issue seemed to be that the certificate didn't contain the workers FQDN. We should also try to switch away from using cert handler: see canonical/observability-libs#112 for more context.