QWindow::showFullScreen, showMaximized, showMinimized broken on wayland

when a qwindow is shown for the first time, in the qpa, QWaylandWindow::setWindowStateInternal() gets called before initWindow()

this makes setWindowStateInternal not work correctly the first time, as mShellSurface isn't existing yet.

then initWindow gets called, and it calls setWindowStateInternal again, but this will fail again due to the guard on mState == state at the beginning

the result will be mShellSurface not having correctly been set as fullscreen