Goal: 

• Kessel is turned on in stage
• Should use kessel browser SDK: https://github.com/project-kessel/kessel-sdk-browser
• Should work similar to backend. First lookup default workspace ID, then check if workspace has correct permission

Acceptance Criteria:

• The UI uses the content-sources-backend  features api to determine whether to use kessel or rbac
• If its supposed to use kessel, call out to those apis to satisfy rbac queries