Clean subgroup labels for survFMM objects A common problem in finite mixture modeling is that subgroup labels are superficial, e.g., the group labeled 'subgroup 1' does not always correspond to the subgroup with the smallest treatment effect. The purpose of this function is to update subgroup labels in order of increasing magnitude of the treatment term such that subgroup 1 always has the smallest treatment term and subgroup 2 always has the largest treatment estimate.