fix(helm): derive metrics Certificate dnsNames from resourceName helper

[kazuki-ma]

Why

The metrics Certificate hardcoded its dnsNames as clickhouse-operator-metrics-service while the metrics Service and the ServiceMonitor's tlsConfig.serverName are rendered through the clickhouse-operator.resourceName helper. With any release name other than the default fullname the SAN never matched and secure scraping failed x509 verification (insecureSkipVerify: false when certManager is enabled).

What

Replaced the two hardcoded dnsNames entries in dist/chart/templates/cert-manager/metrics-certs.yaml with the same clickhouse-operator.resourceName helper (suffix metrics-service) that the metrics Service and the ServiceMonitor already use, so the certificate SANs always follow the rendered Service name.

Verified with helm template myrelease ./dist/chart --namespace demo --set prometheus.enabled=true --set certManager.enabled=true --set metrics.enabled=true --set metrics.secure=true: the Certificate dnsNames and the ServiceMonitor serverName now both render myrelease-clickhouse-operator-metrics-service.demo.svc.

Related Issues

Fixes #290

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