[Synthetics] [Discuss] Journey with 0 completed steps shows as successful

[justinkambic]

Is your feature request related to a problem? Please describe.

Today, when there's a journey with 0 completed steps (i.e. none failed, none passed), we show it as successful in the UI, and allow users to drill into it.

Describe the solution you'd like

When this happens, it's probably better to display some alternative state and disable the click-through functionality.

Describe alternatives you've considered
We could show it as down and also disable click-through. Perhaps also include a tooltip with a long delay, explaining that we can't click in because there are no steps.

Additional context
N/A

[elasticmachine]

Pinging @elastic/observability-design (design)