[9.0](backport #9165) helm: update ksm to 6.1.0 for elastic-agent chart

[mergify]

What does this PR do?

This PR upgrades the kube-state-metrics Helm chart dependency in the elastic-agent Helm chart from version 5.30.1 to 6.1.0.

Why is it important?

• Keeps the dependency up to date with the latest features, metrics, and security patches.
• Reduces the risk of drift from the upstream Prometheus Helm charts.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

None expected. This is a version bump within the supported range and does not introduce breaking changes in the Helm chart interface.

How to test this PR locally

helm install -n kube-system elastic-agent ./deploy/helm/elastic-agent ...

Related issues

• N/A

---

This is an automatic backport of pull request #9165 done by [Mergify](https://mergify.com).

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 805134e

cc @pkoutsovasilis