Add unit test for split_universe

[sonaalKant]

We would like to add some unit test for _split_universe method. https://github.com/kaizen-ai/kaizenflow/blob/a7952ef84cc2ebe93042ccc481486e6ef66ca292/im_v2/common/data/extract/extract_utils.py#L1087

Write 2-3 unit test to check all the corner cases of the method. You will write your tests here

FYI @samarth9008