The specific feature to use an external conda from within the app didn't ship with 2.1, unfortunately. That said, you do have a few options:
1. If you install the program per-user, then UAC will never be invoked, and all of the conda installation will reside inside your AppData directory, and the backstage will install packages to that location.
2. You can create new environments, and use them, from your AppData location, by creating them with Conda. If you run something like `conda create --clone arcgispro-py3 --name my_env` from the command line, it will by default create that new environment in your user profile. You can then use it as you would any other, the only caveat with this approach being that the environment in AppData can't drive Pro itself.
3. You can integrate with an external conda, it just isn't as easy as it should be, and a better approach is being actively worked on.
Cheers,
Shaun