[Build against QT6] Weekly builds w/ QT5 break clipboard ops under Wayland

[penguin-wrangler]

Describe the bug
Attempting to use copy/paste clipboard operations in the weekly builds, built against QT5, does not work when running the AppImage under Wayland.

According to: https://forum.freecad.org/viewtopic.php?p=770777&sid=021fb004d6180362f60c1471a0b9111b#p770777
the problem is only present with QT5, and the clipboard operations work fine when built against QT6.

Any chance the AppImage builds can modernize to build against QT6?

To Reproduce
Steps to reproduce the behaviour:

1. Load any FreeCAD file or make a simple object (say a cube)
2. Select any object, and then do Edit->Copy, or Ctrl-C.
3. Select any amount of the hierarchy to be copied in the Object Selection dialog, and click OK.
4. Error: "(qt.qpa.clipboard) QXcbClipboard::setMimeData: Cannot set X11 selection owner"
5. Result: Object is not copied to the clipboard

[luzpaz]

@adrianinsaval is there an effort to migrate to Qt6 or provide Qt6 builds in parallel to Qt5 ?