[stable/grafana] Avoid data key with an empty value in templates/dashboards-json-configmap.yaml (#17819)

Signed-off-by: ayoub mrini <amrini@wiremind.fr>

stable/grafana/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: grafana
-version: 3.9.0
+version: 3.9.1
 appVersion: 6.3.5
 kubeVersion: "^1.8.0-0"
 description: The leading tool for querying and visualizing time series and metrics.

stable/grafana/templates/dashboards-json-configmap.yaml

@@ -13,6 +13,7 @@ metadata:
     release: {{ $.Release.Name }}
     heritage: {{ $.Release.Service }}
     dashboard-provider: {{ $provider }}
+{{- if $dashboards }}
 data:
 {{- range $key, $value := $dashboards }}
 {{- if (or (hasKey $value "json") (hasKey $value "file")) }}
@@ -28,3 +29,4 @@ data:
 {{- end }}
 {{- end }}
 {{- end }}
+{{- end }}