tdf#124027: use ID of the embedded window

after many trials and errors what LibO apparently expects here is
the ID of QWindow parent of [embedded] system child window

(the rest of the original commit bbe1ede0fada499fd49b60bdc7964e311b331454
is not relevant for LibO 6.2)

Change-Id: Ie4c6d14a50959c0fdd04e745918d4889c9da45ec
Reviewed-on: https://gerrit.libreoffice.org/72458
Tested-by: Jenkins
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>
Reviewed-on: https://gerrit.libreoffice.org/72769
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Tested-by: Michael Weghorn <m.weghorn@posteo.de>
diff --git a/vcl/qt5/Qt5Object.cxx b/vcl/qt5/Qt5Object.cxx
index 3787bc7..499cf190 100644
--- a/vcl/qt5/Qt5Object.cxx
+++ b/vcl/qt5/Qt5Object.cxx
@@ -40,7 +40,7 @@ Qt5Object::Qt5Object(Qt5Frame* pParent, bool bShow)
        m_pQWidget->show();

    m_aSystemData.nSize = sizeof(SystemEnvData);
    m_aSystemData.aWindow = pParent->GetQWidget()->winId();
    m_aSystemData.aWindow = m_pQWindow->winId(); // ID of the embedded window
    m_aSystemData.aShellWindow = reinterpret_cast<sal_IntPtr>(this);
    //m_aSystemData.pSalFrame = this;
    //m_aSystemData.pWidget = m_pQWidget;