Allow Subgroup Members to be visible in Workload Balancer when a Parent Group is added as a filter

[#1]

Currently when you add a Parent group, only members of the parent group show up in the Workload Balancer filter. This means that all sub groups need to be added individually, which defeats the purpose of having a parent group. 

Would like to be able to add a parent group as a filter and all the users in the subgroups under that parent group would show up. This would be consistent with how these group hierarchies work across Workfront.