owcohorts: if only 2 unique values found don't split on whole array

[JakaKokosar]

Issue

Handle edge case where input array is like: [1,1,1,1,1,1,2,2,2,2,2,2,2] and produces only 1 cohort. But there should be two.

Description of changes

Includes

• [X] Code changes
• [ ] Tests
• [ ] Documentation