Fix check for direct rule grant, add unit tests for same

[evankanderson]

Summary

In #5385, I conflated the user_management and machine_accounts flags for enabling direct grants. Unfortunately, this was incorrect, and our smoke tests started to fail when I set the machine_account flag. This should allow re-enabling machine_accounts, while still having smoke tests pass.

Fixes #5145

Change Type

Mark the type of change your PR introduces:

• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

In penance, I updated the AssignRole test to cover the new cases I'd introduced.

Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 57.492% (+0.01%) from 57.481%
when pulling e9c04ca on evankanderson:fix-actions-smoke-testing
into 53e45ae on mindersec:main.