Use MagicMock for unit testing WorkbenchConfig.py

[ysuarez]

Link to Github issue or other discussion

#445

What does this PR do?

This is a simple refactor of the workbench config file unit tests to avoid using a redundant copy of code, and instead use a mock object.

What changes were made?

I replaced a redundant copy of the argparse logic used in the main workbench file with the use of unittest's MagicMock functionality. One reason is to reduce the risk of having a redundant copy of the argparse logic that may get out of sync in the future.

How to test / verify this PR?

Run this CLI command to test:
python3 tests/unit_tests_workbench_config.py -v

All tests should pass.

Interested Parties

@mjordan

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Checklist

• Before opening this PR, have you opened an issue explaining what you want to to do?
• Have you run pycodestyle --show-source --show-pep8 --ignore=E402,W504 --max-line-length=200 yourfile.py?
• Have you included some configuration and/or CSV files useful for testing this PR?
• Have you written unit or integration tests if applicable?
• Does the code added in this PR require a version of Python that is higher than the current minimum version?
• If the changes in this PR require an additional Python library, have you included it in setup.py?
• If the changes in this PR add a new configuration option, have you provided a default for when the option is not present in the .yml file?