[8.x](backport #5912) [helm]: forward agent providers configuration for fleet mode

[mergify]

What does this PR do?

This PR forwards providers configuration for managed agents (fleet mode)

Why is it important?

Because users need to be able to disable/enabled leader election or/and kubernetes providers for managed agents

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 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

N/A

How to test this PR locally

mage helm:renderExamples
mage integration:kubernetesMatrix

Related issues

• Relates Unable to disable Kubernetes Watchers and Leader Election for Fleet Managed Agents #5558

---

This is an automatic backport of pull request #5912 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 9d2c3c9 has failed:

On branch mergify/bp/8.x/pr-5912
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit 9d2c3c9206.
  (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:
	new file:   deploy/helm/elastic-agent/examples/fleet-managed/README.md
	new file:   deploy/helm/elastic-agent/examples/fleet-managed/fleet-values.yaml
	new file:   deploy/helm/elastic-agent/examples/fleet-managed/rendered/manifest.yaml
	modified:   deploy/helm/elastic-agent/templates/agent/k8s/_secret.tpl
	modified:   deploy/helm/elastic-agent/templates/agent/k8s/secret.yaml

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	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
	deleted by us:   deploy/helm/elastic-agent/templates/agent/k8s/_pod_template.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

[pkoutsovasilis]

I think for this PR we should wait for this one #5931 to be merged first and then this one

cc @swiatekm

[elasticmachine]

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

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b mergify/bp/8.x/pr-5912 upstream/mergify/bp/8.x/pr-5912
git merge upstream/8.x
git push upstream mergify/bp/8.x/pr-5912

[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