Make core condition fields required per KEP-1623 (status, lastTransitionTime, reason, message)

[coderabbitai]

Summary

In api/v1/discoveredcluster_types.go, the DiscoveredClusterCondition struct marks status, lastTransitionTime, message, and reason as +optional with omitempty JSON tags. Per KEP-1623 and Kubernetes API conventions, these fields are required in condition objects to ensure complete and valid status reporting.

Required Changes

• Remove // +optional markers from Status, LastTransitionTime, Message, and Reason fields in DiscoveredClusterCondition
• Remove omitempty from their JSON tags
• Keep ObservedGeneration as optional (with omitempty)
• Regenerate CRDs and bundle manifests after applying the change

References

• PR: Add status.conditions to DiscoveredCluster #1988
• Review comment: Add status.conditions to DiscoveredCluster #1988 (comment)
• Requested by: @dislbenn