FIX: License metadata not published in Pypi

[SMoraisAnsys]

Summary

Temporary fix which revert "Apply PEP 639 (#1377)" to avoid the current issue with license metadata not available in Pypi.
Apply changes proposed in #1386 (comment):

• keep Trove classifier (deprecated for now, not removed)
• keep the new PEP 638 fields

Close #1386

[SMoraisAnsys]

Using license = {file = "LICENSE"} could also be an option

[webknjaz]

pypi-publish has been released: https://bsky.app/profile/webknjaz.me/post/3lghhtwey522z. The issue will solve itself as soon as it's bumped in the workflow (and the release happens).