feat(helm): Don't create Secret if existingSecret is provided (#6397)

Author: AntoineFr

ci/helm-chart/templates/secrets.yaml

@@ -1,3 +1,4 @@
+{{- if not .Values.existingSecret }}
 apiVersion: v1
 kind: Secret
 metadata:
@@ -11,8 +12,9 @@ metadata:
     app.kubernetes.io/managed-by: {{ .Release.Service }}
 type: Opaque
 data:
-  {{ if .Values.password }}
+  {{- if .Values.password }}
   password: "{{ .Values.password | b64enc }}"
-  {{ else }}
+  {{- else }}
   password: "{{ randAlphaNum 24 | b64enc }}"
-  {{ end }}
+  {{- end }}
+{{- end }}