[24.2] Add Python 3.13 classifier to packages

[nsoranzo]

Follow-up on #18449 .

Also re-adding the missing newlines at the end of the setup.cfg files, see galaxyproject/galaxy-release-util#29 .

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[github-actions]

This PR was merged without a "kind/" label, please correct.