With UseKubernetesHosting, check pods for the existence of the orleans/serviceId and orleans/clusterId labels

The Kubernetes agent is not able to match pods to silos correctly if the orleans/serviceId and orleans/clusterId labels are missing in the Kubernetes manifest. Therefore the agent will kills pods that it shouldn't be killing.

Specifically The [_podLabelSelector](https://github.com/dotnet/orleans/blob/86e270717bd86f40ec2d42911253ee99be93b9ed/src/Orleans.Hosting.Kubernetes/KubernetesClusterAgent.cs#L50) will not be able to match any Pods:
```
_podLabelSelector = $"{KubernetesHostingOptions.ServiceIdLabel}={_clusterOptions.ServiceId},{KubernetesHostingOptions.ClusterIdLabel}={_clusterOptions.ClusterId}";
```

It could additionally make sense to make sure the label values match the values of the environment variables ORLEANS_SERVICE_ID and ORLEANS_CLUSTER_ID.

Start with src/Orleans.Hosting.Kubernetes/KubernetesClusterAgent.cs, especially the _podLabelSelector construction at the referenced line. Trace how pod labels and the ORLEANS_SERVICE_ID and ORLEANS_CLUSTER_ID environment variables are obtained, then verify that pods missing or disagreeing on the orleans/serviceId and orleans/clusterId labels are not treated as matching silos. Done means the agent no longer kills unrelated pods.

Written by the indexing model from the issue text.