Values.ModifyUserGroupMessageSourceChanges the list of users that belong to the user group.
type nonrec t = {userGroupId : String_.t;The ID of the user group.
*)userIdsToAdd : UserIdListInput.t option;The list of user IDs to add to the user group.
*)userIdsToRemove : UserIdListInput.t option;The list of user IDs to remove from the user group.
*)engine : EngineType.t option;Modifies the engine listed in a user group. The options are valkey or redis.
*)}