jobs: figure out handling for old CreationClusterVersion

Currently we preserve backward compatibility with one or two previous releases, and remove all code that is compatible with older releases.

But there is no migration or anything like that which checks if there are still jobs created at an old version (see [CreationClusterVersion](https://github.com/cockroachdb/cockroach/blob/db5d44dbc96456c8bb555320152b91d42524f6bb/pkg/jobs/jobspb/jobs.proto#L1376))

One option is to automatically fail any jobs that have a `CreationClusterVersion` that is below `MinSupported`. For long lived jobs, it is up to that job specific code to bump the creation version through upgrades.

A bit more context in this discussion: https://github.com/cockroachdb/cockroach/pull/124286#issuecomment-2117917680

Jira issue: CRDB-38842