helm: allow deploying the frontend without sentry dsn in frontend_configmap.yaml

Else the sentry environment is not set which gets.
This was never tested when we added this feature.

Author: BacLuc

.helm/ecamp3/templates/frontend_configmap.yaml

@@ -16,6 +16,7 @@ data:
       SENTRY_ENVIRONMENT: '{{ .Values.domain }}',
     {{- else }}
       SENTRY_FRONTEND_DSN: null,
+      SENTRY_ENVIRONMENT: '{{ .Values.domain }}',
     {{- end }}
       DEPLOYMENT_TIME: '{{ .Values.deploymentTime }}',
       VERSION: '{{ .Values.deployedVersion }}',