Unlike publication which uses a org.elasticsearch.transport.BytesTransportRequest that contains the cluster state as a compressed bytes reference, org.elasticsearch.action.admin.cluster.state.ClusterStateResponse does not compress the cluster state.

This is not ideal when it comes to very large cluster states that are requested via the get-cluster-state REST API from another node as these messages can become quite sizable. We should align the behavior here and use the same serialization approach in this message that we use for publication to limit the size of a full cluster state transport message (which will generally compress very well because settings and mappings tend to be duplicated heavily across indices).

relates #77466