Move habitat dependencies

[jiuguangw]

Instead of commenting out the habitat dependencies, I moved them to a different group such that they can be installed via a pip install -e .[habitat]. This should also fix the import cv2 error in one of the tests. I didn't touch the pre-commit error.

[jiuguangw]

Oh well, I guess there is indeed a gym version conflict:

    zsos[habitat] 0.1 depends on gym>=0.26.2
    habitat-lab 0.2.520230729 depends on gym<0.23.1 and >=0.22.0

I think it was still worth it to move the habitat stuff to a different group, we'll just leave it alone for now...

[naokiyokoyamabd]

Oh great, thanks! I was putting off figuring how to do different sets of installs, this is great to know about