Fix conda-specific assumptions

[ZLLentz]

Expected Behavior

The tests should pass regardless of if we install the library via conda, pip, or manually via setup.py or otherwise

Current Behavior

There are some explicit checks for conda-related environment variables here:

hutch-python/hutch_python/cli.py

Line 136 in 297a577

base = str(Path(os.environ['CONDA_EXE']).parent.parent)

and potentially similar shenanigans elsewhere.

Context

PIP build fails