Include Overlay Qml type in Material, Universal (...) themes

Overlay.modal can be used for customizing the dialog background:

import QtQuick 2.12
import QtQuick.Controls 2.3

Dialog {
	// Prevent background dimming
	Overlay.modal: Item {
	}
}

But this works only with the "QtQuick.Controls" import. Using "QtQuick.Controls.Material", "QtQuick.Controls.Univeral" (...?) does not work:

import QtQuick 2.12
import QtQuick.Controls.Material 2.3

Dialog {
	// Prevent background dimming
	Overlay.modal: Item {
	}
}

Please extend the themes so that the Overlay can also be used there (so that the qmlint/qmlsc compilation fix can be used: https://www.qt.io/blog/compiling-qml-to-c-qtquick-controls-and-optional-imports).