fdo#77600 RTF export: always close URL's before the end of run

In case the URL text has multiple portions, then MSWordExportBase
generates multiple URL's anyway, and this helps to avoid loosing some
direct formatting of the remaining portions of the paragraph.

(cherry picked from commit 55c832d86e6cb06e9d6423ce5e6245189bc80da1)

Conflicts:
	sw/source/filter/ww8/rtfattributeoutput.cxx
	sw/source/filter/ww8/rtfattributeoutput.hxx

Change-Id: Ifd72741de610ce69b9ae0978aa8f9a532a3aeed2
Reviewed-on: https://gerrit.libreoffice.org/9124
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>