[SPARK-55585][K8S]: Allow executor feature steps to create resources

[EnricoMi]

What changes were proposed in this pull request?

Applies resources provided by the executor feature step.

Why are the changes needed?

Spark provides feature steps that allow for custom configuration of Kubernetes driver and executor pods. While driver feature steps can create resources, executor feature steps cannot.

The KubernetesExecutorSpec allows for defining executorKubernetesResources, but they are not created (applied) by the ExecutorPodsAllocator. Only PVCs are specifically created right now.

Does this PR introduce any user-facing change?

Kubernetes resources defined by an executor feature step are actually created.

How was this patch tested?

Unit test.

Was this patch authored or co-authored using generative AI tooling?

No

[EnricoMi]

This is how the driver is doing the same thing:

spark/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesClientApplication.scala

Line 177 in 22c1464

kubernetesClient.resourceList(otherKubernetesResources: _*).forceConflicts().serverSideApply()