Changes to Get activities (localized) manageable by activity managers of a group. Roles: admin, group activity manager.

added the optional property contents/items/managerAudienceId to the response with the 200 status

added the optional property error/errorId to the response with the 400 status

added the optional property error/errorId to the response with the 401 status

added the optional property error/errorId to the response with the 403 status

added the optional property error/errorId to the response with the 404 status

added the optional property error/errorId to the response with the 500 status