Typo: `threshold_samples_set_idx` is not a bool

[gordon-lim]

In examples/paper_replication/runner.py: :param bool threshold_samples_set_idx: (default 1) Which set of threshold samples to use (based on index) However in examples/paper_replication/small_dataset_aum.sh, the value of threshold_samples_set_idx was provided as 2.