fix: double quoting causing nxdomain (#6039)

Signed-off-by: Bryan Lee <me@bryanl.ee>
(cherry picked from commit 5262026)

Author: 6ixfalls

charts/kube-ovn-v2/templates/pinger/pinger-daemonset.yaml

@@ -81,13 +81,12 @@ spec:
           {{- else if eq .Values.networking.stack "IPv6" -}}
           {{ .Values.pinger.targets.externalAddresses.v6 }}
           {{- end }}
-          - --external-dns=
           {{- if eq .Values.networking.stack "Dual" -}}
-          "{{ .Values.pinger.targets.externalDomain.v6 }}"
+          - --external-dns={{ .Values.pinger.targets.externalDomain.v6 }}
           {{- else if eq .Values.networking.stack "IPv4" -}}
-          "{{ .Values.pinger.targets.externalDomain.v4 }}"
+          - --external-dns={{ .Values.pinger.targets.externalDomain.v4 }}
           {{- else if eq .Values.networking.stack "IPv6" -}}
-          "{{ .Values.pinger.targets.externalDomain.v6 }}"
+          - --external-dns={{ .Values.pinger.targets.externalDomain.v6 }}
           {{- end }}
           - --ds-namespace={{ .Values.namespace }}
           - --logtostderr=false