tdf#131434 ensure expander icon column is created

which the normal ::insert case does, but the bulk insert omitted

Change-Id: I9b236e5f0e91292539164d39f0f90e109a1b503e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/90928
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/vcl/source/app/salvtables.cxx b/vcl/source/app/salvtables.cxx
index e64e801..cf83fa8 100644
--- a/vcl/source/app/salvtables.cxx
+++ b/vcl/source/app/salvtables.cxx
@@ -3534,9 +3534,11 @@ public:
        if (pFixedWidths)
            set_column_fixed_widths(*pFixedWidths);

        Image aDummy;
        for (int i = 0; i < nSourceCount; ++i)
        {
            aVclIter.iter = new SvTreeListEntry;
            aVclIter.iter->AddItem(std::make_unique<SvLBoxContextBmp>(aDummy, aDummy, false));
            m_xTreeView->Insert(aVclIter.iter, nullptr, TREELIST_APPEND);
            func(aVclIter, i);