Fix the KAS Kubernetes detail dashboards

This reverts a change to the KAS metrics from !4335 (merged) that resulted in empty Kubernetes detail dashboards for KAS:

• https://dashboards.gitlab.net/d/kas-kube-deployments/kas-kube-deployment-detail
• https://dashboards.gitlab.net/d/kas-kube-containers/kas-kube-containers-detail

Snapshots:

• https://dashboards.gitlab.net/dashboard/snapshot/ZoYWQ14nomkD0wdJVe25ltNNAC9IqmLj - kas: Kube Containers Detail
• https://dashboards.gitlab.net/dashboard/snapshot/u5KjpvgVDRExUIe3knTWgz3yDaU2Qufk - kas: Kube Deployment Detail

cc/ @andrewn