fdo#75757: remove inheritance to std::vector

Change-Id: I07daec0ced64d0ca6ad2dd06fd19a1c7366e5c31
Reviewed-on: https://gerrit.libreoffice.org/10921
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>