Feature Description

Summary
Add support for configuring priorityClassName in the TestRun specification to allow pods to be scheduled with a specific Kubernetes PriorityClass.

Motivation
In environments with limited resources or where scheduling pressure is common, pods may be evicted due to low priority. Since the k6 operator/controller does not currently restart evicted pods, test reliability can suffer.
By allowing users to assign a priorityClassName to TestRun pods, we can reduce the likelihood of eviction and improve test stability in production-like or resource-constrained environments.

Suggested Solution (optional)

Extend the TestRun CRD to optionally accept a priorityClassName field that will be applied to the resulting test pod(s). For example:

apiVersion: k6.io/v1alpha1
kind: TestRun
metadata:
  name: sample-test
spec:
  script:
    configMap:
      name: test-script
      file: test.js
  runner:
    priorityClassName: high-priority

This would propagate the priorityClassName value into the pod spec generated by the operator.

Already existing or connected issues / PRs (optional)

No response