Remove Qt Compat Graphic effects

[strseb]

Description

My build with Qt 6.11 fails to create the QML window, due to an error in Qt5 GraphicEffects Compat module.
it might just be a blip with my build, but i thought thats a good opportunity to replace the old compat module with Qt6 QML Effects.

Note given i'm using RectangularShadow - so we now have MINIMUM reqiurement of Qt 6.9. If we want to avoid that, i probably could also use the multi-effect element, just like the others.

[oskirby]

This is awesome, I would love to be rid of the Qt5 compat module, but I don't think we can merge this until we drop support for our PPA builds as those are holding us back to Qt 6.2.4 (Jammy) and Qt 6.4.2 (Noble).

[mcleinman]

This is awesome, I would love to be rid of the Qt5 compat module, but I don't think we can merge this until we drop support for our PPA builds as those are holding us back to Qt 6.2.4 (Jammy) and Qt 6.4.2 (Noble).

@strseb with this, do you want a review now, or should we hold this for a bit?

[strseb]

I think Let's keep it in limbo for a bit until we have control over that. Marking this as Draft for now