The goal of this ticket is to rename "clientID" to "clientId" in service accounts API responses. 

Affected API endpoints:
/groups/{uuid}/principals/ used with principal_type=service-account
/principals/ used with type=service-account

The reason for the change is to make the param name consistent with 
https://sso.stage.redhat.com/auth/realms/redhat-external/apis/service_accounts
so we don't have to distinguish between two different names on the frontend side and use the same types and interfaces easier