Fix extra hemisphere-children from jba3-175

Example: While CM (Amygdala) right should have extra children CM.AAA right, CM.Ce , CM.Me right from 175-oncology, it also had the left. This was due to improper handling of the high granular region tree. (The oncology jsons are not shipped as left and right but we add them. Hence, one needs to consider this during the creation of parcellation json, which led to the problem when we switched from 157 to 175).