[Feature Request]: hyprqt6engine

### Description

Useful If we want to separate HyDE + hyprland to another DE. Setting `QT_QPA_PLATFORMTHEME` to `hyprqt6engine` should let us customize Qt apps without breaking KDE plasma theming. 

Native KDE apps are exception as they are using kdeglobals not the native QT.  

### Use Case

na

### Proposed Solution

na

### Alternatives

na

### Additional Information

na