CI: Fix gtk version and build

[soreau]

No description provided.

[soreau]

@az0 The one thing I noticed on this build in the logs, under Test the build, it says:

PyGObject not available: No module named 'gi'

Just figured I'd point this out. Otherwise, it seems ok.

[az0]

✅ gtk3.24-x86-windows is now artifact 80.1M (more in line with previous , and way down from 290MB in your last PR)
✅ "vcpkg build" step shows gtk 3.24.51 and not 3.24.4x
✅ PyGObject not available in the "build python and PyGTK job" is okay because it gets built in the dependent job

The 2h43min for the first job is better than 3h14m for your last PR. This is not great, though, and I am working on re-adding vcpkg caching.

Thank you, Scott!