fdo#72697 actually write this only in ODF 1.2 extended

(cherry picked from commit 49f9694e34d07468cff4a7e4de332f11be3e0dd8)

Conflicts:
	xmloff/source/text/txtflde.cxx

Change-Id: I32097cc4b8a67615b0b6d6172cafd0edad7469b6
(cherry picked from commit 4031765b004dded31f04c54f9a055b7a3d0053f2)
Reviewed-on: https://gerrit.libreoffice.org/7078
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>