tdf#92918 Engineering notation lost with Add/Delete Decimal Place

With scientific format, use the trick of thousand separator to detect
Engineering notation.

Change-Id: I7acdfb8bec646f9d6c1a17c334b60fa9708c8111
Reviewed-on: https://gerrit.libreoffice.org/17406
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
diff --git a/sc/source/ui/view/viewfunc.cxx b/sc/source/ui/view/viewfunc.cxx
index a027ace..ce48261 100644
--- a/sc/source/ui/view/viewfunc.cxx
+++ b/sc/source/ui/view/viewfunc.cxx
@@ -2543,6 +2543,12 @@ void ScViewFunc::ChangeNumFmtDecimals( bool bIncrement )
            nPrecision = aOut.getLength() - nPos - aDecSep.getLength();
        // else keep 0
    }
    else
    {
        if ( (nOldType & css::util::NumberFormat::SCIENTIFIC) && !bThousand &&
             (pOldEntry->GetFormatIntegerDigits()%3 == 0) && pOldEntry->GetFormatIntegerDigits() > 0 )
            bThousand =  true;
    }

    if (!bError)
    {