[kube-prometheus-stack] Default Grafana dashboards retain "cluster" label in PromQL even when disabled

[ArjonBu]

Describe the bug a clear and concise description of what the bug is.

When disabling multi-cluster support or the cluster label in the kube-prometheus-stack Helm values, the default Grafana dashboards deployed by the chart still hardcode the "cluster" label inside the PromQL queries. This leads to graphs not working unless the "cluster" label is removed.

What's your helm version?

version.BuildInfo{Version:"v4.0.1", GitCommit:"12500dd401faa7629f30ba5d5bff36287f3e94d3", GitTreeState:"clean", GoVersion:"go1.25.4", KubeClientVersion:"v1.34"}

version.BuildInfo{Version:"v3.19.4", GitCommit:"7cfb6e486dac026202556836bb910c37d847793e", GitTreeState:"clean", GoVersion:"go1.24.11"}

What's your kubectl version?

Client Version: v1.35.1 Kustomize Version: v5.7.1 Server Version: v1.34.1

Which chart?

kube-prometheus-stack

What's the chart version?

83.5.0

What happened?

No response

What you expected to happen?

Dashboards render without the cluster label.

How to reproduce it?

No response

Enter the changed values of values.yaml?

grafana:
  fullnameoverride: "grafana"
  defaultDashboardsTimezone: "Europe/Berlin"
  defaultDashboardsEditable: false
  sidecar:
    dashboards:
      multicluster:
        global:
          enabled: false
        etcd:
          enabled: false

Enter the command that you execute and failing/misfunctioning.

helm template kube-prometheus-stack prometheus-community/kube-prometheus-stack \
  --version 83.5.0 -f values.yaml

Anything else we need to know?

No response