fdo#79062 File having Footnote with Text Effect got corrupted after RT

When we do the export of the file, In the footnotes.xml,
 the w14 namespaces were not being added.

This issue exists for EndNotes as well.

Reviewed-on: https://gerrit.libreoffice.org/9439
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>
(cherry picked from commit 4002fae08754aec38873bc453f991773ec6536f0)

Conflicts:
	sw/qa/extras/ooxmlexport/ooxmlexport.cxx

Change-Id: I6494bbf1beaa0666743d9c1bb85a64f8bda20398