Area chart also doesn't support label position property.

Change-Id: I612ca7426b2b3de07d4afe1d78cd809f1f6b37bb
diff --git a/oox/source/export/chartexport.cxx b/oox/source/export/chartexport.cxx
index 027a566..0845f71 100644
--- a/oox/source/export/chartexport.cxx
+++ b/oox/source/export/chartexport.cxx
@@ -2640,6 +2640,7 @@ void ChartExport::exportDataLabels(
            aParam.mbExport = true;
        break;
        case chart::TYPEID_DOUGHNUT:
        case chart::TYPEID_AREA:
            // Doughnut charts don't support label placement.
            aParam.mbExport = false;
        break;