LineEdit and TextEdit component can not use 'ctrl + v' to paste in caps lock mode

[ogoffart]

As reported in https://github.com/slint-ui/slint/issues/4198

LineEdit and TextEdit component can not use 'ctrl + v' to paste in caps lock mode (Or ctrl + c, or ctrl + a, ...)

I could reproduce this on X11 with the winit backend in Slint 1.3 The Qt backend works well. It might have worked in Slint 1.2