fdo#75757: remove inheritance to std::vector

Change-Id: Ia2f03e08199f23fd1b226db2c7e0bfade07bf0f0
Reviewed-on: https://gerrit.libreoffice.org/10719
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>