Deleting the requirement for the track to have a vertex.
Since TightPrimary and LoosePrimary working points of InDetTrackSelection do not impose any requirements on the vertex, the check for the track to have a vertex link caused the code to skip a lot of good tracks during the MC input file creation for the RNN PID algorithm. This commit adds a config option (CheckTrackVertex, set to true by default) to bypass such check.