Source Poetry version from ASDF where available

[palfrey]

Tell us more.

I've got a private project using the self-hosted runner, and there was an ASDF update of the Poetry version. I wanted to add a postUpgradeTasks to update the Poetry lock for the new version when Poetry gets updated, but the version of Poetry in the environment is being sourced from the lock file i.e. the previous version of Poetry.

If an ASDF .tool-versions file with poetry <version> is available, I think this should be the first place to source the local Poetry version, not the lockfile.

[rarkins]

Converted to issue: #33470