refactor(admin_audit): improve type safety and clarity in Action logging

[joshtrichards]

• Resolves: #

Summary

Changes:

• Improved type safety and robustness
• Enhanced error reporting
• Improved code clarity
• Better audit log output
• Unit tests for Action

The original implementation had several edge cases that could produce unclear audit logs:

• Boolean false values appeared as empty strings (invisible in logs)
• Null values were indistinguishable from empty strings
• Format string mismatches would crash rather than log the error
• Variable names ($elements, $text) didn't clearly convey their purpose
• Missing keys were reported one at a time rather than all at once

This refactoring makes the audit logging more defensive, maintainable, and produces clearer output for security auditing purposes.

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)