Fix masked license validation test names (#5257)

[harishwargad]

Fixes #5257

Summary

This PR addresses issue #5257 where license rule file pairs mapped to the exact same dynamically generated Python validation test method names (e.g., cnri-python-1.6.1.RULE and cnri-python-1.6_1.RULE both producing cnri_python_1_6_1_rule), causing tests to overwrite/mask each other during dynamic test generation.

Building on the initial test setup from stale PR #5258, this PR completes the rule file renames.

Changes Made

• Renamed cnri-python-1.6_1.RULE -> cnri-python-1.6-v1.RULE and proprietary_10.RULE -> proprietary_10_alt.RULE using git mv so generated safe Python method names are unique.
• Added a regression test in tests/licensedcode/test_rule_file_names.py to ensure all rule file names generate unique safe Python method names in the future.
• Updated CHANGELOG.rst and AUTHORS.rst.

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)

Signed-off-by: @harishwargad