Materials in User Assets are shown when there's no Quick3D import

Found issue:

• In Content Library - Materials we show text "To use Content Library, first add the QtQuick3D module in the Components view" and no materials can be added before that.
• In Content Libary - User Assets - Materials all materials are shown even without QtQuick3D Import and can be added
• -> I would expect either the same logic as in Content Library - Materials, or for the user it might be easier that QtQuick3D is automatically added if material is added to project.