[PR #1310/c7fa1454 backport][3.32] Switch content 2.4 metadata upload test to use attrs package to avoid race condition with large sync test

[patchback]

This is a backport of PR #1310 as merged into main (c7fa145).

test_basic_pulp_to_pulp_sync uses the large python fixture to populate Pulp which includes setuptools. On sync we don't populate the metadata_version field since it isn't exposed in the pypi/json api, so if this test runs first then setuptools will not have the field set when the content is reused on the upload test. We should come up with a better long term solution but for now this should work.

📜 Checklist

• Commits are cleanly separated with meaningful messages (simple features and bug fixes should be squashed to one commit)
• A changelog entry or entries has been added for any significant changes
• Follows the Pulp policy on AI Usage
• (For new features) - User documentation and test coverage has been added

See: Pull Request Walkthrough