[Bug Report] buildkite artifact download (v3) seems not respect --include-retried-jobs when --step is provided

Hi, I am working on a feature works on a retry job and artifact from the job before the retry need to be fetched.

`agent artifact download foo bar` failes, but `buildkite-agent artifact download foo bar --include-retried-jobs` works, so I assumes by default it would not download matched artifact from a failed job?

Then `--step` is added because, but
`agent artifact download foo bar --step step_key --include-retried-jobs` fails with
> No artifacts found for downloading

While
`agent artifact download foo bar --step step_label --include-retried-jobs` fails with
> 404 A step could not be found matching: `job_label`

So I assumes `--step` should accept step key, otherwise it should give 404. But it seems that when `--job` is provided, `--include-retried-jobs` isn't respected properly so that artifacts from the failed job can't be found?

Reproduce the reported `agent artifact download` commands with `--step` and `--include-retried-jobs`, comparing a step key with a step label. Trace the artifact-download entry point and its handling of retried jobs; done when matching artifacts from the failed job are found with a step key and invalid step identifiers produce the expected error.

Written by the indexing model from the issue text.