Expose metrics-api in splice-validator helm chart

[RRaule]

Hi, I am unable to prometheus scrape annotations as the port for splice-validator. We do not use Prometheus operator on our clusters. In docs, it states I should. This currently works for participant but not validator.

Configuring a helm deployment to enable metrics (https://docs.dev.global.canton.network.sync.global/deployment/observability/metrics.html#configuring-a-helm-deployment-to-enable-metrics)

To enable metrics in a helm deployment, set the metrics.enabled value to true (default false) in the helm values. This will create a ServiceMonitor kubernetes custom resource. For this to work it would require that the Prometheus operator is installed in the cluster.

Alternatively you can add prometheus scrape annotations to the charts that are configured to scrape port 10013.

Could the following lines get added to the validator deployment ports

        - containerPort: 10013
          name: metrics-api
          protocol: TCP

[RRaule]

Created a PR to help
#386