🧪 Add unit tests for format_security_list

[ffalcinelli]

🎯 What: Added unit tests for format_security_list in src/config.rs.
📊 Coverage: The tests now cover all key scenarios:

• Empty lists (returns [])
• A single entry with only a reference
• A single entry with a reference and a tag
• A single entry with all fields (reference, tag, timestamp)
• Multiple entries to test the comma formatting and line breaks correctly.
  ✨ Result: Enhanced the test suite coverage and verified correct handling of format_security_list output formatting, improving overall codebase reliability.

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PR created automatically by Jules for task 10680917875961530029 started by @ffalcinelli

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