[8.16](backport #6079) [helm] remove unsupported Release fields for publishing the chart as EKS addon

[mergify]

What does this PR do?

This PR removes unsupported fields Release.IsInstall, Release.IsUpgrade, and .Release.Service from the Helm chart. These fields are unavailable in the EKS addon and their presence leads to Helm chart validation failures when using the AWS console. The changes ensure compatibility with EKS addon requirements by refactoring the chart to exclude these fields.

Why is it important?

This change is crucial for ensuring that the Helm chart used in the Elastic Agent EKS addon passes AWS console validations. Unsupported fields prevent us from publishing this Helm chart as an EKS addon.

Checklist

• 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 changes 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

This PR should not cause any direct disruption to users, but it will ensure smoother integration and deployment in AWS EKS environments.

How to test this PR locally

1. Try to publish the packaged Helm chart as an EKS add-on and you will see no validation errors 🙂

Related issues

• Closes [helm] Remove Unsupported Release Fields from Helm Chart for EKS Addon Compatibility #6053

  ---

  This is an automatic backport of pull request [helm] remove unsupported Release fields for publishing the chart as EKS addon #6079 done by Mergify.

[mergify]

Cherry-pick of 5cd2518 has failed:

On branch mergify/bp/8.16/pr-6079
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit 5cd2518b4e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   deploy/helm/elastic-agent/templates/NOTES.txt
	modified:   deploy/helm/elastic-agent/templates/agent/_helpers.tpl

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   deploy/helm/elastic-agent/examples/eck/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/fleet-managed/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/kubernetes-default/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/kubernetes-hints-autodiscover/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/kubernetes-only-logs/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/multiple-integrations/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/nginx-custom-integration/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/system-custom-auth-paths/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/user-cluster-role/rendered/manifest.yaml
	both modified:   deploy/helm/elastic-agent/examples/user-service-account/rendered/manifest.yaml

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[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]

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