Bug: listHostsMetrics response mapping mismatch (clustermetrics -> cluster) causes null parsing

The CloudStack backend response for listClustersMetrics "command" has changed its JSON structure, but the cloudstack-go wrapper is still parsing the old field (hostmetrics).

This results in host metrics being returned as null in the Go SDK response.

API: listClustersMetrics (command)
Client: github.com/apache/cloudstack-go/v2

Key change:
The backend now returns metrics under the field host, not hostmetrics.

Start with the listClustersMetrics API mapping in the cloudstack-go wrapper and compare its response field handling with the backend response described here. Verify that host metrics are read from host rather than hostmetrics, then run the relevant SDK tests or a listClustersMetrics request to confirm the returned metrics are no longer null. An open pull request already addresses this issue.

Written by the indexing model from the issue text.