Backport fix for mixed-DPI window calculations

There is a bug in Qt 6.3.2 and QT 6.2.6 where windows can be shown with wrong size calculations. This bug is not present in Qt 6.4.0; it would be great to backport the fix to Qt 6.2 LTS.

Code

// main.qml
import QtQuick.Controls.Material

ApplicationWindow {
    width: 640
    height: 480
    visible: true

    ConfigurationWindow { id: config }

    Button {
        text: "Pop Up"
        onClicked: config.show()
    }
}

// ConfigurationWindow.qml
import QtQuick.Controls.Material

ApplicationWindow {
    id: popup
    width: 360
    height: 240
/*
    // WORKAROUND: "Overriding" Window.show() like this forces the correct calculations
    function show() {
        popup.visible = true
        popup.width += 1
        popup.width -= 1
    }
*/
    Button {
        text: "I am right-aligned"
        anchors.right: parent.right
    }

    onVisibleChanged: {
        if (popup.visible)
            console.log("Popup size:", popup.width, 'x', popup.height)
    }
}

Steps to reproduce

1. Set up 2 screens, where the primary screen has 125% scaling and the secondary screen has 100% scaling
2. Build and run the attached project
3. Drag the main window to the secondary screen
4. Click "Pop Up"
5. Close the popup window
6. Click "Pop Up" again

Outcomes for Qt 6.2/6.3 (wrong)

Console output:

qml: Popup size: 360 x 240
qml: Popup size: 288 x 192

The pop-up window looks like right-align-wrong1.png the first time, then r_ight-align-wrong2.png_ the second time.

Outcomes for Qt 6.4 (correct)

Console output:

qml: Popup size: 360 x 240
qml: Popup size: 360 x 240

The pop-up window looks like right-align-correct.png both times.

Workaround

After show()-ing the popup window, increment then decrement the window width. This seems to force the correct calculations.