`azdev setup` fails to call `python` executable from conda environment on win32

Start in azdev/utilities/command.py at the py_cmd function and inspect how the Python executable is selected on win32. Reproduce azdev setup from an activated conda environment, then verify that package installation invokes the environment's working Python executable instead of the invalid Scripts/python path.

When running azdev setup from within a conda environment on win32, the py_cmd function in azdev/utilities/command.py attempts to run Scripts/python from within the current conda env, rather than the python executable in the root of the environment:

(base) PS> conda activate az-dev
(az-dev) PS> azdev setup --cli <repopath> --repo <repopath>



=======================
| Azure CLI Dev Setup |
=======================



Azure CLI:
<repopath>



Azure CLI extension repos:
<repopath>



Installing packages
=====================



Upgrading pip...
Command `C:\Users\<username>\AppData\Local\Continuum\anaconda3\envs\az-dev\Scripts\python -m pip install --upgrade pip` failed with exit code 1:
'C:\Users\<username>\AppData\Local\Continuum\anaconda3\envs\az-dev\Scripts\python' is not recognized as an internal or external command,
operable program or batch file.

As a workaround, modifying py_cmd to call sys.executable rather than using env_path seems to work:

def py_cmd(command, message=False, show_stderr=True, raise_error=False, is_module=True, **kwargs):
    """ Run a script or command with Python.
    :param command: The arguments to run python with.
    :param message: A custom message to display, or True (bool) to use a default.
    :param show_stderr: On error, display the contents of STDERR.
    :param raise_error: On error, raise CommandError.
    :param is_module: Run a Python module as a script with -m.
    :param kwargs: Any kwargs supported by subprocess.Popen
    :returns: CommandResultItem object.
    """
    from azdev.utilities import get_env_path
    env_path = get_env_path()
    python_bin = sys.executable
    if is_module:
        command = '{} -m {}'.format(python_bin, command)
    else:
        command = '{} {}'.format(python_bin, command)
    return cmd(command, message, show_stderr, raise_error, **kwargs)