pip: fix bug with parsing requirements

When parsing the pip report, parsing some requirements could fail, as the packaging library used for the parsing was different from the one used by pip internally.

This makes sure that always the pip internals packaging library is used, which should prevent inconsistencies like that.

pkgs/fetchPipMetadata/src/fetch_pip_metadata/lock_file_from_report.py

@@ -1,10 +1,8 @@
-import os
-import sys
 import subprocess
 import json
 from pathlib import Path
 
-from packaging.requirements import Requirement
+from pip._vendor.packaging.requirements import Requirement
 from packaging.utils import (
     canonicalize_name,
 )