tdf#151417 crash in draw, activating Form controls

regression from
    commit 8611f6e259b807b4f19c8dc0eab86ca648891ce3
    Author: Noel Grandin <noel.grandin@collabora.co.uk>
    Date:   Thu May 27 10:27:46 2021 +0200
    ref-count SdrObject

Change-Id: I1798cead8ed72ad59799c40d0e99f3424f9e382b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/141134
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
diff --git a/svx/source/svdraw/svdouno.cxx b/svx/source/svdraw/svdouno.cxx
index 09de889..82832c9 100644
--- a/svx/source/svdraw/svdouno.cxx
+++ b/svx/source/svdraw/svdouno.cxx
@@ -139,6 +139,7 @@ SdrUnoObj::SdrUnoObj(
:   SdrRectObj(rSdrModel),
    m_pImpl( new SdrUnoObjDataHolder )
{
    osl_atomic_increment(&m_refCount); // prevent deletion during creation
    m_bIsUnoObj = true;

    m_pImpl->pEventListener = new SdrControlEventListenerImpl(this);
@@ -146,6 +147,7 @@ SdrUnoObj::SdrUnoObj(
    // only an owner may create independently
    if (!rModelName.isEmpty())
        CreateUnoControlModel(rModelName);
    osl_atomic_decrement(&m_refCount);
}

SdrUnoObj::SdrUnoObj( SdrModel& rSdrModel, SdrUnoObj const & rSource)