tdf#132278 crash after opening an old file

regression from
    commit 7282014e362a1529a36c88eb308df8ed359c2cfa
    tdf#50916 Makes numbers of columns dynamic.

Change-Id: I7a37631094b91f4859326db054f285daa8dccbb8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92740
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
(cherry picked from commit 4faf8ef2553aba31d6021abce604f7716d2ad229)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92544
Reviewed-by: Michael Stahl <michael.stahl@cib.de>
diff --git a/sc/source/core/data/dociter.cxx b/sc/source/core/data/dociter.cxx
index 919c41c7..f501bb8 100644
--- a/sc/source/core/data/dociter.cxx
+++ b/sc/source/core/data/dociter.cxx
@@ -324,7 +324,8 @@
    ScTable* pTab = rDoc.FetchTable(nTab);
    if (!pTab)
        return nullptr;

    if (nCol >= pTab->GetAllocatedColumnsCount())
        return nullptr;
    return &pTab->aCol[nCol].maCells;
}