The Portland City Council moved Thursday evening toward approving a nonbinding term sheet for a Moda Center renovation in which the city would contribute $120 million in exchange for a lease keeping the Trail Blazers in town for at least 20 years. That means the Portland City Council is now the lone holdout. The term sheet advanced by the council this week, even after more than a dozen amendments proposed by various councilors to change it, remained unaltered from the term sheet that city negotiators announced in mid-July. The desire to hold all parties to the deal settled in closed-door meetings last spring may explain why, despite its displeasure, the council did nothing to alter the term sheet this week. A final vote on the city’s term sheet will take place Aug. 12.