fdo#75757 Remove inheritance to std::vector

Change-Id: I5d5746869e47a1d25d6bec28452394e215d4427d
Reviewed-on: https://gerrit.libreoffice.org/13483
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>