Remove move() in ImageOverlay

it was causing the full screen image overlay to appear on the "primary
display" vs. the actual display nheko is running on.

removing the move() call makes the overlay follow the window.

src/dialogs/ImageOverlay.cpp

@@ -43,7 +43,6 @@ ImageOverlay::ImageOverlay(QPixmap image, QWidget *parent)
 
         screen_ = QGuiApplication::primaryScreen()->availableGeometry();
 
-        move(QApplication::desktop()->mapToGlobal(screen_.topLeft()));
         resize(screen_.size());
 
         connect(this, SIGNAL(closing()), this, SLOT(close()));