CI: multiple segfaults for Python 3.14

[loichuder]

Seems to be linked to OpenGL:

• test_nexus_dataviewer.py::test_3d_scatter: https://github.com/silx-kit/silx/actions/runs/28649929935/job/84965244103?pr=4651
• silx/gui/plot/test/test_plotwidget.py::testResizeWidget: https://github.com/silx-kit/silx/actions/runs/28649152940/job/84962728686?pr=4670

[t20100]

Test with a larger CI matrix: https://github.com/silx-kit/silx/actions/runs/28652270209