Fix: corrected etcd multi-cluster dashboard bug

[BahmaniAlireza]

What this PR does / why we need it

This PR fixes the etcd Grafana dashboard shipped with kube-prometheus-stack.
The existing dashboard did not correctly filter by cluster name in multi‑cluster environments, causing metrics from multiple clusters to be aggregated together.

We updated the dashboard definition in templates/grafana/dashboards-1.14/etcd.yaml to add a cluster variable and adjust the PromQL queries. With this change, the dashboard now works correctly when:

• A single cluster is selected
• Multiple clusters are selected
• The “All” option is used

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes #

Special notes for your reviewer

• The change was applied directly to etcd.yaml under dashboards-1.14.
• Tested locally with Helm upgrade; verified the generated ConfigMap contains the updated JSON.
• Validated in Grafana that the cluster dropdown now filters metrics correctly.

Checklist

• [ ] DCO signed
• [ ] Chart Version bumped
• [ ] Title of the PR starts with chart name (e.g. [kube-prometheus-stack] fix etcd dashboard cluster filter)

[QuentinBisson]

Hey @BahmaniAlireza did you check the top of the file https://github.com/BahmaniAlireza/helm-charts/blob/592c28beacded53b817fb54ebdc7ef2bc91a8ac6/charts/kube-prometheus-stack/templates/grafana/dashboards-1.14/etcd.yaml#L4?

[jkroepke]

@QuentinBisson i have the feeling that etcd maintainers dont care about dashboard anymore @TheRealNoob also had conversations with the etcd maintainer. I feel the feeling that we should not longer consume upstream and fork the dashboard into the repo. If you agree, I would appreciate, if you could assists the user here.