fix: skip invalid user defaults plists

[Ricardo08S]

Summary

• Harden Application User Defaults artifact against invalid plist files so corrupt entries are logged and skipped instead of crashing the entire artifact.

Implementation Details

• Imports logfunc and emits a clear message when a plist fails to parse (both plistlib and biplist code paths).
• Ensures only dictionaries are iterated, preventing AttributeError when the file is malformed or contains unexpected types.
• Keeps the rest of the reporting pipeline unchanged.