Don't fullscreen windows from the showEvent

Martin says this probably results in the loops, and setting window state
to fullscreen from constructor should be enough.

components/fullscreenpanel.cpp

@@ -95,7 +95,7 @@ void FullScreenPanel::showEvent(QShowEvent *event)
 {
     using namespace KWayland::Client;
     QQuickWindow::showEvent(event);
-    setWindowState(Qt::WindowFullScreen);
+//    setWindowState(Qt::WindowFullScreen);
 }