Scope UI should indicate when it can't find an Agent

[abuehrle]

Minor issue, but when you don't have Prometheus configured on your host, the UI should be able to detect that and tell you that it doesn't find one. Instead, it shows an activity indicator and perhaps it should just grey out the prometheus button or just show a message that says it can't find an agent.

[abuehrle]

I saw the new UI. Looks great.

[abuehrle]

One minor point though. It might be good to show all of the agents in the settings panel all together, i.e. Flux, Cortex and Scope and maybe even Net too for consistency sake.

[abuehrle]

I will log this over at Weave Cloud, and close it.