Description of problem:

If a helm endpoint action ends with the error, the returned response is not a valid json content.


How reproducible:

POST request at /api/helm/manifest/releases with the following payload

{
	"chart_url": "foo"
}


Actual results:

{
  "error": "Failed to install helm chart: failed to download \"foo\" (hint: running `helm repo update` may help)"
}null

Expected results:

{
  "error": "Failed to install helm chart: failed to download \"foo\" (hint: running `helm repo update` may help)"
}