test: Improve Test Coverage for `package_list_parser.py`

[JigyasuRajput]

Description:

cve_bin_tool/package_list_parser.py lacks sufficient test coverage.

Functions Needing Tests:

1. parse_list(self) ~ report

   • Parses package lists from different package managers (dpkg, rpm, pacman, pip).
   • Needs tests for different distributions, missing packages, and JSON output parsing.

2. add_vendor(self, vendor_package_pairs) ~ report

   • Associates vendors with package names using CVE database data.
   • Needs tests for vendor matching and edge cases where no vendor is found.

3. parse_data(self) ~ report

   • Converts parsed package data into structured output.
   • Needs tests for handling missing or malformed data.

4. check_file(self) ~ report

   • Validates the package list file before parsing.
   • Needs tests for handling missing files, incorrect formats, and invalid package lists.

[JigyasuRajput]

There was a hiccup, I need to update this issue

[JigyasuRajput]

updated the issue!
I checked the old reports by mistake

[JigyasuRajput]

Hey! I'm working on this issue