Fix issue with exclusions in config files and env vars

[joshtemple]

Change description

Previously, we were converting leading dashes in --explores and --folders args into tildes so they wouldn't break argparse. However, this meant we built our exclusion logic deeper in the application off of leading ~ instead -. For args passed via the config file or environment variables, preprocessing wasn't happening, so the leading dashes were not being converted to tildes.

Rather than keep everything in tildes, I thought it would be better to simply "undo" the preprocessing for command-line arguments after parsing is done.

This reverts the validator logic back to using - instead of ~, cleaning up the tilde-prepended args before they're passed out of the CLI. This also makes tests more readable.

Description here

Type of change

• Bug fix (fixes an issue)
• New feature (adds functionality)

Related issues

Closes #526

Checklists

Security

• Security impact of change has been considered
• Code follows security best practices and guidelines

Code review

• Pull request has a descriptive title and context useful to a reviewer