Fix export of Multi-level category axis labels with the correct OOXML tags (as the OOXML Standard requested) in the correct order. Also fix tdf#126195: but only the export part of the whole fault, which combined (united) the text of the category axis labels at different levels. Change-Id: Iefcef00818a3bb2ee1671bf693335904be471722 Reviewed-on: https://gerrit.libreoffice.org/75299 Reviewed-by: László Németh <nemeth@numbertext.org> Tested-by: László Németh <nemeth@numbertext.org>