Note readiness gate failures in Pod summary UI

[crenshaw-dev]

Summary

The Pod summary should show some indication that a readiness gate is failing.

Motivation

Readiness probes produce events when they fail. Users know to look at the Events tab for those failures. But for readiness gates, you have to dig through the status field to figure out what's wrong.

Proposal

Show a small alert near the top of the Pod summary UI indicating that a readiness gate is failing.

[Marvin9]

Is there a difference between readiness gates and probes or same?

[crenshaw-dev]

It's a slightly different thing: https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#pod-readiness-gate