Require Jenkins 2.414.3 or newer

[car-roll]

Require Jenkins 2.414.3 or newer

Also removes tests that relied on an empty cloud name being allowed.

was originally downstream of https://github.com/jenkinsci/jenkins/pull/8310 but that has now been abandoned

since Jenkins 2.403, it is no longer possible to create a cloud with an empty name. This fixes tests that create empty clouds.

Testing done

N/A - changes only in test automation are well covered by ci.jenkins.io

### Submitter checklist
- [x] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [x] Ensure that the pull request title represents the desired changelog entry
- [x] Please describe what you did
- [x] Link to relevant issues in GitHub or Jira
- [x] Link to relevant pull requests, esp. upstream and downstream changes
- [x] Ensure you have provided tests - that demonstrates feature works or fixes the issue

[car-roll]

Note: https://github.com/jenkinsci/jenkins/pull/8310 has now been closed, but i think the test changes for this PR will be needed whenever the jenkins version is bumped past 2.403. This is when cloud name is not allowed to be empty https://github.com/jenkinsci/jenkins/blob/5665665b6b7bf45cc3102338477540029a4d8f62/core/src/main/java/hudson/slaves/Cloud.java#L121

[MarkEWaite]

@car-roll I assume this does not require a new release but can be included in the next release whenever that happens. Is that correct?

[car-roll]

@MarkEWaite yes, that's correct. It was more about just not having someone else going through resolving those same issues I went through if I closed this PR completely