Terrorists plotted to kill “tens of thousands” of people at Taylor Swift’s concert in Vienna. The 34-year-old pop star was forced to cancel three dates on her ‘Eras’ tour in the Austrian capital earlier this month due to a planned attack at the Ernst Happel Stadium before officials arrested three teenagers, and a CIA official has now revealed the US intelligence agency played a major part in thwarting the “quite advanced” plot. CIA Deputy Director David Cohen is quoted by ABC News as saying: “They were plotting to kill a huge number — tens of thousands of people at this concert, including I am…