Wrong error message or status code

https://github.com/kubev2v/migration-planner/blob/988443cbacdc2a805e5cfa410f37e558acf81b6c/api/v1alpha1/openapi.yaml#L248

Unsounds: 500 is an internal server error and the code for resource not found is 404 (which indicates a client requested a resource that doesn't exist). Please align the API so consumers can have a better understanding of the API behavior