Bug fixes and cleanup for test infrastructure:
- schema_test.go: Fix SchemaVersion reference with proper manifest import
- schema_test.go: Update all schema.json paths to internal/manifest location
- manifestenv.go: Remove unused helper functions (isArtifactsType, getPackagePath)
- nobaredetector.go: Fix exprToString syntax error, remove unused functions
All tests now pass without errors or warnings
