fdo#75757: remove inheritance to std::vector

by replacing it with a typedef.

Change-Id: Iaa88086e3c5195012982dd625bfd589de2e484a2
Reviewed-on: https://gerrit.libreoffice.org/11017
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>