Custom Roles in Explore

Feature Request Summary: 

Along with the roles of Admin, Agent, End User in Explore datasets, the custom roles that an instance has should be available as well.

Description/Use Cases: 

Being able to pull the information of agents in reporting rather than scrolling through the role's list of agents in the admin center or via the api is more efficient. This would be useful for auditing access levels as well as potentially highlighting cherry-picking behavior.

One commenter's scenario: Building a report on the number of solved tickets per agent over a given time frame, sorted by custom role. "Agents" is not specific enough in this case, as I need to separate out multiple "mini departments" within our CX instance to accurately measure the number of inbound agents needed to handle the incoming volume.

Business impact of limitation or missing feature:

Different roles have different permissions and being able to audit efficiently for role is an important part of security.

Other necessary information or resources:

Pulling comment information from this post: https://support.zendesk.com/hc/en-us/articles/4408843316762