main: Convert to device independent coordinates for scaling

devicePixelRatioF() returns the scaling ratio when high dpi scaling is enabled.
When high dpi scaling is enabled, the raw screen coordinate system is scaled to device independent coordinates.

src/yuzu/applets/qt_software_keyboard.cpp

@@ -575,7 +575,7 @@ void QtSoftwareKeyboardDialog::MoveAndResizeWindow(QPoint pos, QSize size) {
     QDialog::resize(size);
 
     // High DPI
-    const float dpi_scale = qApp->screenAt(pos)->logicalDotsPerInch() / 96.0f;
+    const float dpi_scale = screen()->logicalDotsPerInch() / 96.0f;
 
     RescaleKeyboardElements(size.width(), size.height(), dpi_scale);
 }