Call gi.require_version before importing, instead of after

[selfisekai]

___________________________________________________ ERROR collecting tests/test_scheduler/test_mainloop/test_gtkscheduler.py ____________________________________________________
tests/test_scheduler/test_mainloop/test_gtkscheduler.py:16: in <module>
    gi.require_version("Gtk", "3.0")
/usr/lib/python3.12/site-packages/gi/__init__.py:121: in require_version
    raise ValueError(
E   ValueError: Namespace Gtk is already loaded with version 4.0
=============================================================================== warnings summary ================================================================================
tests/test_scheduler/test_mainloop/test_gtkscheduler.py:13
  /home/lauren/aports/community/py3-rx/src/RxPY-4.1.0/tests/test_scheduler/test_mainloop/test_gtkscheduler.py:13: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '4.0') before import to ensure that the right version gets loaded.
    from gi.repository import GLib, Gtk  # isort: skip

[coveralls]

coverage: 93.453%. remained the same
when pulling 8276c08 on selfisekai:gi-require_version-before-import
into d0b472b on ReactiveX:master.