bugfix: use correct service-account-issuer in case of custom clusterDomain (#2342)

* fix service account issuer for custom cluster domain

* set clusterdomain value in _coredns.tpl

Author: vardhaman-surana

chart/templates/_coredns.tpl

@@ -16,7 +16,7 @@ Corefile: |-
       {{- if .Values.networking.advanced.proxyKubelets.byHostname }}
       rewrite name regex .*\.nodes\.vcluster\.com kubernetes.default.svc.cluster.local
       {{- end }}
-      kubernetes cluster.local in-addr.arpa ip6.arpa {
+      kubernetes{{ if and (.Values.networking.advanced.clusterDomain) (ne .Values.networking.advanced.clusterDomain "cluster.local") }} {{ .Values.networking.advanced.clusterDomain }}{{ end }} cluster.local in-addr.arpa ip6.arpa {
           {{- if .Values.controlPlane.coredns.embedded }}
           kubeconfig /data/vcluster/admin.conf
           {{- end }}