Remove the use of PaginatedResult's totalNumberOfResult
After discussed with other engineers, we decided to not adding nextPageToken to PaginatedResults. That approach requires us to eventually change all existing API that return PaginatedResults to take a nextPageToken. Instead, clients can try to iterate through the result set without using totalNumberOfResults. If there is a case when totalNumberOfResults is being used to report count to users, a new count service should be added.