GitHub Actions: Tox runs Python 3.14t tests on Python 3.12

[cclauss]

Python 3.14 works as expected, but free-threaded Python 3.14t does not...

Python 4.14 tests run on: platform linux -- Python 3.14.0, pytest-8.4.2, pluggy-1.6.0

• https://github.com/kivy/python-for-android/actions/runs/18323516154/job/52182271732#step:5:42

Python 4.14t tests run on: platform linux -- Python 3.12.3, pytest-8.4.2, pluggy-1.6.0

• https://github.com/kivy/python-for-android/actions/runs/18323516154/job/52182271768#step:5:42

@kuzeyron @T-Dynamos Any hints on this problem?