`show` crashes with QWaylandGLContext::makeCurrent: eglError: 3002, this: 0x55d3e3bc9f20 on some Linux configuration

[abey79]

Full error log:

QOpenGLWidget: Failed to make context current
Cannot find EGLConfig, returning null config
QEGLPlatformContext: Failed to make temporary surface current, format not updated (3002)
QWaylandGLContext::makeCurrent: eglError: 3002, this: 0x55d3e3bc9f20 

This affect all version of vpype, including 1.12.1 and pre-1.12.

Relevant discord convo: https://discord.com/channels/499297341472505858/748589023731122277/1045404083529449564

Workaround appears to be QT_QPA_PLATFORM=xcb.

[abey79]

Duplicates #596