The lease is a contract; both parties are bound by its terms, and neither party may add new terms or requirements unilaterally, without the consent of the other. If the lease required you to contribute towards the building's cable or to use a cable service specified by the landlord, then the landord may require this; if the lease does not say anything about cable, then the landlord may not. You need to reference the specific terms of the lease to answer the question.