Fix #4609: Handle file-type license references in NuGet packages

[NullPointer-cell]

Fixes #4609

Problem
When scanning NuGet packages that reference license files (like [email protected]), the parser was dumping the raw XML dict instead of extracting the actual file path. This made the output pretty useless for anyone trying to find the license.

Before:

"extracted_license_statement": "{'@type': 'file', '#text': 'tools\\\\LICENSE.txt'}"

After:

"extracted_license_statement": "See file at tools\\LICENSE.txt"

What changed?

The parser now checks if the license element has type="file" and extracts the path properly:

if license_type == 'file':
    extracted_license_statement = f"See file at {license_text}"

Pretty straightforward - just needed to handle the dict structure that xmltodict returns when parsing <license type="file">path</license>.

Testing

Ran all the NuGet tests - 10/10 passing. Also verified:

• [email protected] now shows "See file at tools\LICENSE.txt" ✓
• URL-based licenses (like in the bootstrap package) still work fine ✓
• Expression-based licenses unchanged ✓

The "unknown" declared license is expected here since we can't actually determine the license type without reading the file itself.

Files changed

• src/packagedcode/nuget.py - the actual fix
• Test fixtures for the python package (nuspec, expected output, license file)

Checklist:

• Tests pass
• No breaking changes
• Signed commit
  Signed-off-by: NullPointer-cell
  [email protected]

[NullPointer-cell]

@capfei sir
I would like you to review my pr and I would be happy to any recommendation on changes