Bug 511284

If the main window and the child window both have an Action with the same shortcut, then the Action in the main window is triggered, even if the child window is focused.

Here's a demo app showcasing this

```
import QtQuick
import QtQuick.Controls
import org.kde.kirigami as Kirigami

Kirigami.ApplicationWindow {
    id: window
    width: 800
    height: 800
    visible: true
    title: qsTr("Hello World")
    Component.onCompleted: window.pageStack.pushDialogLayer(page1, {})

    Component {
        id: page1
        Kirigami.Page {
            id: p1
            Action {
                shortcut: 'Escape'
                onTriggered: p1.closeDialog()
            }
            Shortcut {
                sequences: [ "down" ]
                onActivated: console.log("down")
            }
        }
    }
    Action {
        shortcut: 'Escape'
        onTriggered: console.log(1111)
    }
    Action {
        shortcut: 'down'
        onTriggered: console.log(2222)
    }
}
```

When the child window is open, pressing down, regardless how many time, only triggers the main window Action.
When pressing escape, first it triggers the main window Action, then the Action in the window opened by pushDialogLayer.