fdo#75757: remove inheritance to std::vector

Change-Id: I265d3a51a4eabee734e7ac15841f56bcae0807e4
Reviewed-on: https://gerrit.libreoffice.org/10916
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>