Fix Logging in ManageOperators Class

[mcdonnnj]

🗣 Description

This PR fixes an issue with a logging message and makes some small edits to improve readability and consistency.

💭 Motivation and context

I was testing a bash script that uses this today and when using the add command twice ran into an error with logging output:

--- Logging error ---
Traceback (most recent call last):
  File "/Users/mcdonnnj/.pyenv/versions/3.9.1/lib/python3.9/logging/__init__.py", line 1079, in emit
    msg = self.format(record)
  File "/Users/mcdonnnj/.pyenv/versions/3.9.1/lib/python3.9/logging/__init__.py", line 923, in format
    return fmt.format(record)
  File "/Users/mcdonnnj/.pyenv/versions/3.9.1/lib/python3.9/logging/__init__.py", line 659, in format
    record.message = record.getMessage()
  File "/Users/mcdonnnj/.pyenv/versions/3.9.1/lib/python3.9/logging/__init__.py", line 363, in getMessage
    msg = msg % self.args
TypeError: not all arguments converted during string formatting
Call stack:
  File "/Users/mcdonnnj/.pyenv/versions/manage-cyhy-ops/bin/manage-cyhy-ops", line 33, in <module>
    sys.exit(load_entry_point('manage-cyhy-ops', 'console_scripts', 'manage-cyhy-ops')())
  File "/Volumes/workspace/my-repos/manage-cyhy-ops/src/manage_cyhy_ops/cli.py", line 151, in main
    manager.add_user(username, ssh_key, overwrite=overwrite_ssh_key)
  File "/Volumes/workspace/my-repos/manage-cyhy-ops/src/manage_cyhy_ops/manageoperators.py", line 140, in add_user
    return self._update_cyhy_ops_users(username)
  File "/Volumes/workspace/my-repos/manage-cyhy-ops/src/manage_cyhy_ops/manageoperators.py", line 91, in _update_cyhy_ops_users
    logging.info(log_msg, username, self.region)
Message: 'Successfully performed no operations on CyHy Operators in region "%s"'
Arguments: ('first.last', 'us-east-1')

While fixing that issue I improved the output phrasing and made changes to keep all the logging consistent as a result.

🧪 Testing

Automated testing passes. I verified that the modified version does not exhibit the error mentioned above.

WARNING SSH key for "first.last" already exists in the Parameter Store for region "us-east-1".
WARNING If you need to overwrite this value, please use the "--overwrite" switch.
WARNING User "first.last" is already in the list of active CyHy Operators in region "us-east-1".
INFO Performed no operations for "first.last" in region "us-east-1"

✅ Checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All new and existing tests pass.

[dav3r]

LGTM! ⛔ 🐞
Please note my single-character suggestion.

[jsf9k]

LGTM!

[dav3r]

Solid! 🎸