`SnapExporter` is started on install

[chanchiwai-ray]

SnapExporter is started on install event, which is not the currently expected behavior: exporter are only started when cos_agent is related.

[gabrielcocenza]

SmartCTL exporter is enabled by default, which means that it will start immediately after the strategy finish installing it. If we really want this to happen then we need to stop and disable all snaps after installing

[chanchiwai-ray]

I think this is also true for dcgm: https://github.com/canonical/hardware-observer-operator/blob/main/src/service.py#L391-L402. We should be consistent with the approach: either remove cos_agent check or make the snap disable on install

[chanchiwai-ray]

I am leaning towards removing cos_agent check in this charm because the if cos_agent_related check in config_changed event will silently block the config changed of exporter.

[samuelallan72]

My 2c: I'd also lean towards always running the exporter, ignoring the status of cos-agent relation. It makes the logic simpler, and avoids confusion for anyone who wants to run or test the exporter without relating cos. So we can go with always starting/enabling the snap services on install (or leaving the default if enabled by default).