gh-144412: Require tuple args in pickle REDUCE

[sabasiddique1]

Summary

• Require tuple args in pickle.load_reduce() to match _pickle
• Add regression test for non-tuple REDUCE args

• Issue: Python pickle load_reduce function doesn't check if args is a tuple #144412

[python-cla-bot]

All commit authors signed the Contributor License Agreement.

[bedevere-app]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.