unused since 9fb7aaf570 "Make linked graphic
register into LinkedManager again", and remove further function parameters and
class members that turn out to be unused now, too
Change-Id: I3dd2b138fd8787d12b89547526da751ea5954845
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/106041
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>