Taylor Swift's "The Official Release Party of a Showgirl" opened at No. 1 at the U.K. and Ireland box office over the weekend with £3.5 million ($4.7 million), according to Comscore. Warner Bros.' "One Battle After Another" ranked second with $2.7 million, pushing its cumulative total to $8.1 million after two weekends. Universal's "Downton Abbey: [...]