Add reason to `Ready` condition if probe is cause and/or distinct condition for probe

Please describe the solution you would like.

In https://github.com/vmware-tanzu/vm-operator/pull/480, a VM was deployed with a GuestInfo-based readiness probe. However, when the Ready condition transitioned to False or True, there was no Reason associated with the condition. If a readiness probe causes the VM's Ready condition to transition to True or False, then there should be some indication that this is the Reason for the condition's value. That or there should be some distinct condition related to readiness probes.

Is there anything else you would like to add?

See above.

Please tell us about your environment.

kubectl -n vmware-system-vmop get pods \
  -ojsonpath='{range .items[*].spec.containers[*]}{.image}{"\n"}{end}' | \
  sort -u | \
  grep vmop | \
  awk -F'/' '{print $3}' | \
  awk -F: '{print $2}'

Start by tracing how the VM operator updates the Ready condition when a GuestInfo-based readiness probe changes, using the behavior described around PR 480. Compare the current condition transition with the probe-handling path, then define whether completion means adding a probe-specific Reason or introducing a distinct readiness-probe condition, with coverage for both True and False transitions.