wayland: Don't raise window when entering fullscreen mode

If the window is inactive and it enters fullscreen mode for some reason, it can create a situation where keyboard goes to a window occluded by the fullscreen window.

This change makes XdgToplevelClient::setFullScreen() not raise the window. It's the responsibility of whoever requested the fullscreen mode change.

If the configure event is acknowledged, the window's stack layer will be invalidated and recomputed. If the window is active, it will be promoted to the ActiveLayer, otherwise its stack position won't change.