Fix/4447 upgrade grafana helm chart

[souben]

What type of PR is this?

/kind cleanup

What this PR does / Why we need it

The Grafana Helm chart currently used by the project has been deprecated.
The chart was migrated to grafana-community/helm-charts effective January 30, 2026.
Running make minikube-setup-grafana produces a deprecation warning, and this PR is to migrate the project from grafana/grafana to grafana-community/grafana.

Note that a previous PR (#4449) addressing the issue was submitted previously, but it was stalled for around a week due to licencing issue, so this PR was submitted as a backup.

Changes

1. build/Makefile

Updated the setup-grafana target:
Old:

helm repo add grafana https://grafana.github.io/helm-charts
helm upgrade grafana grafana/grafana ...

New:

helm repo add grafana-community https://grafana-community.github.io/helm-charts
helm upgrade grafana grafana-community/grafana ...

The uninstall-grafana target remains unchanged since it references the release name.

2. build/grafana.yaml and build/grafana-frontend.yaml

Reviewed for compatibility with the new chart.
Current values work with the upgraded chart. Verified by installing the new chart and confirming dashboards load correctly.

3. Documentation

Updated site/content/en/docs/Guides/metrics.md:

• Replaced the old repository URL with https://grafana-community.github.io/helm-charts
• Updated helm repo add and helm upgrade commands to use grafana-community

Updated the build/docs/make-reference.md to reference the new Grafana Helm chart.

Which issue(s) this PR fixes

Closes #4447

[markmandel]

We should also update the make reference please!

build/docs/make-reference.md

[souben]

Sure @markmandel. I missed that one.
All is set now.

[markmandel]

/gcbrun

[agones-bot]

Build Succeeded 🥳

Build Id: e9e8d3e7-c99b-415f-a907-3e439c0e47b6

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.57.0-dev-cb7315a
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.57.0-dev-cb7315a
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.57.0-dev-cb7315a-linux
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.57.0-dev-cb7315a
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.57.0-dev-cb7315a
• image: us-docker.pkg.dev/agones-images/ci/agones-processor:1.57.0-dev-cb7315a
• Linux C++ SDK (build): agonessdk-1.57.0-dev-cb7315a-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.57.0-dev-cb7315a.zip

A preview of the website (the last 30 builds are retained):

• https://cb7315a-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/googleforgames/agones.git pull/4454/head:pr_4454 && git checkout pr_4454
helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.57.0-dev-cb7315a

[mikeseese]

Just needs this one missed update; I can't see any more references other than in vendor/k8s.io/apimachinery/pkg/util/managedfields/node.yaml which I believe is negligible.