[otel/kube-stack] Update the OpenTelemetry Kube Stack Helm Chart to v0.12.4

[rogercoll]

What does this PR do?

Bumps the tested kube-stack Helm Chart version

Why is it important?

Fixes usage with Helm v4 open-telemetry/opentelemetry-helm-charts#1967

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

How to test this PR locally

Related issues

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

[mergify]

This pull request does not have a backport label. Could you fix it @rogercoll? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-./d./d is the label that automatically backports to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.

[elasticmachine]

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

[github-actions]

@Mergifyio backport 9.1 9.2

[mergify]

backport 9.1 9.2

✅ Backports have been created

• #11592 [9.1] (backport #11541) [otel/kube-stack] Update the OpenTelemetry Kube Stack Helm Chart to v0.12.4 has been created for branch 9.1
• #11593 [9.2] (backport #11541) [otel/kube-stack] Update the OpenTelemetry Kube Stack Helm Chart to v0.12.4 has been created for branch 9.2