Use mamba env export with --json

[mathbunnyru]

Describe your changes

Issue ticket if applicable

Checklist (especially for first-time contributors)

• I have performed a self-review of my code
• If it is a core feature, I have added thorough tests
• I will try not to use force-push to make the review process easier for reviewers
• I have updated the documentation for significant changes

[mathbunnyru]

It seems that it was fixed in the upstream and let's use json to have less dependencies: mamba-org/mamba#3559

When new mamba is released, I will check that it works now. If not I will let mamba team know.

[mathbunnyru]

The upstream has released mamba v2 version where this issue is almost fixed.

Unfortunately, there is a bug in the case of using the --from-history flag.
When the issue is fixed in the upstream we'll be able to merge this PR.

mamba-org/mamba#3582

[mathbunnyru]

mamba 2.0.4 has been released, so this is fixed, and it won't prevent us from updating to mamba v2.
So, I'm merging this