What does this PR do?

Modifies the kube-stack configurations to prevent "null" values in the Helm v4.

Why is it important?

Fixes the deployment with Helm 4, error message:

Error: Instrumentation.opentelemetry.io "elastic-instrumentation" is invalid: spec.env: Invalid value: "null": spec.env in body must be of type array: "null"
OpenTelemetryCollector.opentelemetry.io "opentelemetry-kube-stack-gateway" is invalid: [spec.config.service.pipelines.metrics/aggregated-otel-metrics.processors: Invalid value: "null": spec.config.service.pipelines.metrics/aggregated-otel-metrics.processors in body must be of type array: "null", <nil>: Invalid value: "null": some validation rules were not checked because the object was invalid; correct the existing errors to complete validation]

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?
• ...