fdo#75757: remove inheritance to std::vector

Change-Id: I1874b5b4a059ef5fc8818b3b49ff10f2917b20ca
Reviewed-on: https://gerrit.libreoffice.org/11135
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>