[Multi_K8s-Plugin] Add config validation for KubernetesApplicationSpec#6747

Warashi merged 7 commits into

pipe-cd:masterpipe-cd/pipecd:masterfrom

mohammedfirdouss:feat/multicluster-config-validationmohammedfirdouss/pipecd:feat/multicluster-config-validationCopy head branch name to clipboard