QScreen: Apply high-DPI scale to availableGeometry size, not position

Treat geometry and availableGeometry in the same way so the position
is in native coordinates and only the size is scaled.

Task-number: QTBUG-128660
Change-Id: If1355014fd6dd1a204cab7177d7941c980dda0ad
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/gui/kernel/qscreen.cpp

@@ -61,7 +61,8 @@ void QScreenPrivate::updateGeometry()
     qreal scaleFactor = QHighDpiScaling::factor(platformScreen);
     QRect nativeGeometry = platformScreen->geometry();
     geometry = QRect(nativeGeometry.topLeft(), QHighDpi::fromNative(nativeGeometry.size(), scaleFactor));
-    availableGeometry = QHighDpi::fromNative(platformScreen->availableGeometry(), scaleFactor, geometry.topLeft());
+    QRect nativeAvailableGeometry = platformScreen->availableGeometry();
+    availableGeometry = QRect(nativeAvailableGeometry.topLeft(), QHighDpi::fromNative(nativeAvailableGeometry.size(), scaleFactor));
 }
 
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