Automatically test discoverable KMS

[jimmykarily]

We introduced a test here: https://github.com/kairos-io/kcrypt-challenger/pull/45/files#diff-7b5de4f9b392e3c469cc56719eb808add9da3a962994c0a891f761a8fc57a6be

but it doesn't work so we skipped it to unblock the release. We should make it work and enable it.