fix: only show missing authToken warning if release.create is true

[eni4sure]

Fixes #536

[lforst]

Hi, unfortunately we cannot merge this PR as-is because it will actually change whether the release management plugin is added or not, which controls a bunch of other things too. We would need to be a little bit smarter about this.

[eni4sure]

@lforst That makes sense. I pushed an update to explicitly check if both release.create and release.finalize is set to false to disable releases. That should avoid any unintended changes.