Add annotation for external-dns to create the kiali fqdn entry

What

The change adds an annotation to the Istio ingress values, which will create a fully qualified domain name (FQDN) entry for Kiali using external-dns. This will make it easier to access Kiali from outside the cluster.

Why

Related Issue: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24159

Diff:

► ConfigMap/istio-ingress/reliability-overlay-istio-ingress-values-pre-gitlab-gke drifted

data.values.yaml
  ± value change in multiline text (two inserts, one deletion)
      labels:
        gl_product_stage: eng-infra-reliability
        gl_dept_group: eng-infra-reliability-foundations
        gl_dept_group:
      resources:
        requests:
          cpu: 500m
          memory: 512Mi
        limits:
          cpu: 2000m
          memory: 2048Mi
      autoscaling:
        minReplicas: 2
      serviceAnnotations:
        external-dns.alpha.kubernetes.io/hostname: kiali.pre-gitlab-gke.pre.gitlab.net