Test meta gen cleanup 2

[TimothyMakkison]

Remove unused models and functions

See #4563

[thomhurst]

Summary

This PR removes unused models and functions from TestMetadataGenerator.

Critical Issues

None found ✅

Verdict

✅ APPROVE - This is a clean code cleanup PR that:

• Removes 9 unused model files (verified they are only referenced in the files being deleted)
• Removes 8 unused functions from TestMetadataGenerator
• Removes unused local variables (compilation, methodName)
• Removes unused parameters from function signatures
• Minor whitespace cleanup

All changes have been verified:

• Deleted models are not referenced anywhere else in the codebase
• Removed functions are not called
• Function signature changes correctly update all call sites
• No source generator output changes, so no snapshot test updates needed

The cleanup makes the codebase more maintainable without changing behavior.