K8SSAND-1804 ⁃ imageConfig parsing bugs with single version override + registry override

[burmanm]

What happened?
If I override a single Cassandra version to something like "k8ssandra:4.0.0" and add a new imageRegistry override to "ghcr.io", I end up with just "ghcr.io/" and nothing else. This is because of missing closures in the imageRegistry parsing.

Did you expect to see something different?

How to reproduce it (as minimally and precisely as possible):

Environment

• Cass Operator version:

  Insert image tag or Git SHA here

  * Kubernetes version information:

  kubectl version

  * Kubernetes cluster kind:

insert how you created your cluster: kops, bootkube, etc.

• Manifests:

insert manifests relevant to the issue

• Cass Operator Logs:

insert Cass Operator logs relevant to the issue here

Anything else we need to know?:

┆Issue is synchronized with this Jira Task by Unito
┆friendlyId: K8SSAND-1804
┆priority: Medium