Delete coreDNS components during vcluster delete op

[ApsTomar]

What issue type does this pull request address? (keep at least one, remove the others)
/kind bugfix

What does this pull request do? Which issues does it resolve? (use resolves #<issue_number> if possible)
resolves ENG-7242

Please provide a short message that should be published in the vcluster release notes
Fixed an issue where coreDNS components don't get deleted during vcluster delete operation

What else do we need to know?

[FabianKramm]

I think we can simplify this, we can just do

 err := client.AppsV1().Deployments(namespace).DeleteCollection(ctx, metav1.DeleteOptions{}, metav1.ListOptions{LabelSelector: labelSelector})
if err != nil {
  errs = append(errs, err)
}

 err = client.CoreV1().Pods(namespace).DeleteCollection(ctx, metav1.DeleteOptions{}, metav1.ListOptions{LabelSelector: labelSelector})
if err != nil {
  errs = append(errs, err)
}
			services, err := client.CoreV1().Services(namespace).List(ctx, metav1.ListOptions{LabelSelector: labelSelector})
			if err != nil {
				return err
			}
			if len(services.Items) != 0 {
				for _, svc := range services.Items {
					err = client.CoreV1().Services(namespace).Delete(ctx, svc.Name, metav1.DeleteOptions{})
					if err != nil {
  errs = append(errs, err)
					}
				}

I don't see the reason why we need an array of functions here to iterate over, just makes the code harder to understand.

[ApsTomar]

@FabianKramm Made the suggested changes, please take a look.