graphics/qt6-svg: Fix text rendering in FreeCAD

qt6-svg has a bug that causes some text rendering to display as a path
instead of as text. The code was fixed upstream:
https://bugreports.qt.io/browse/QTBUG-123817

The effect of this bug include that technical drawings from FreeCAD with
svg templates print or export to PDF with mangled description blocks:
https://github.com/FreeCAD/FreeCAD/issues/18881

PR: 287659