Wrong versions in charts are not reported back to chart-assignment status

[ensonic]

If one specifies a bad version in an app.yaml / chartassignment.yaml the chart will be stuck in LoadingChart and one needs to consult the chartassignment-controller logs to see

Error: "retrieve chart: chart "kyverno" version "1.12.1" not found in https://kyverno.github.io/kyverno/ repository"

We should check that case here:
https://github.com/googlecloudrobotics/core/blob/main/src/go/pkg/controller/chartassignment/release.go#L206

and report the error instead of retrying.