This takes the loading time from 15s to 14s.

Reduce unnecessary allocation/copying by passing down ownership of the
newly created ScPatternAttr to the item pool

Change-Id: Iec38bbff572d10ff8d86f5e65fbe9a96b6a5a706
Reviewed-on: https://gerrit.libreoffice.org/71010
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>