feat(conda): add licenses support for `environment.yml` files

[DmitriyLewen]

Description

Add licenses support for environment.yml files. Licenses are taken from conda-meta directory. Path to conda-meta is determined from prefix field of environment.yml

Related issues

• Close #5949
• Close #6566

Checklist

• [x] I've read the guidelines for contributing to this repository.
• [x] I've followed the conventions in the PR title.
• [x] I've added tests that prove my fix is effective or that my feature works.
• [ ] I've updated the documentation with the relevant information (if needed).
• [ ] I've added usage information (if the PR introduces new options)
• [ ] I've included a "before" and "after" example to the description (if the PR is a user interface change).