Use more specific command to list environments

[patricklabatut]

Description

This small change uses the more specific env list command instead of info to retrieve the list of environments. micromamba doesn't dump environments in the output of the info --json command, so while the change doesn't modify anything when using standard conda, it unblocks using conda-pack together with micromamba.

Checklist - did you ...

• [x] Add a file to the news directory (using the template) for the next release's release notes?
• [x] Add / update necessary tests?
• [x] Add / update outdated documentation?

[conda-bot]

We require contributors to sign our Contributor License Agreement and we don't have one on file for @patricklabatut.

In order for us to review and merge your code, please e-sign the Contributor License Agreement PDF. We then need to manually verify your signature, merge the PR (https://github.com/conda/infrastructure/pull/823), and ping the bot to refresh the PR.

[patricklabatut]

@xhochy Thanks! Sure, I had actually signed the CLA shortly after seeing this being required. It looks to me the matching PR in the infrastructure repo did acknowledge that (with the cla-signed label) but is still lacking a review stamp...

[xhochy]

@patricklabatut Can you look into the failures here? They are related to your change.