Automatic update cannot update ArtifactTool under elevated & unelevated command prompt

### **This is autogenerated. Please review and update as needed.**

## Describe the bug
Trying to download a universal package from Azure Dev Ops using the AZ command line tool. Run command to download and it fails at the download of ArtifactTool.

**Command Name**
`az artifacts universal download
Extension Name: azure-devops. Version: 0.4.0.`

**Errors:**
```
[WinError 2] The system cannot find the file specified
Traceback (most recent call last):
pip-install-3pnsb50r\knack\knack\cli.py, ln 206, in invoke
cli\core\commands\__init__.py, ln 608, in execute
cli\core\commands\__init__.py, ln 666, in _run_jobs_serially
cli\core\commands\__init__.py, ln 657, in _run_job
azext_devops\dev\common\exception_handler.py, ln 22, in azure_devops_exception_handler
reraise(*sys.exc_info())
Temp\pip-install-3pnsb50r\six\six.py, ln 703, in reraise
cli\core\commands\__init__.py, ln 636, in _run_job
...
Azure\CLI2\lib\subprocess.py, ln 709, in __init__
restore_signals, start_new_session)
Azure\CLI2\lib\subprocess.py, ln 997, in _execute_child
startupinfo)
FileNotFoundError: [WinError 2] The system cannot find the file specified
```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- `az artifacts universal download --organization {} --feed {} --verbose --name {} --version {} --path {}`

## Expected Behavior

It downloads the universal package.

## Environment Summary
```
Windows-10-10.0.19041-SP0
Python 3.6.6

azure-cli 2.1.0

Extensions:
azure-devops 0.4.0

```
## Additional Context