fdo#75757: remove inheritance to std::vector

from ApiTokenVector.

Change-Id: Ie924e0e01db74b925a7f6063f8ce7fd952d04381
Reviewed-on: https://gerrit.libreoffice.org/11290
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>