Manhattan federal prosecutors declined to appeal a judge's ruling that barred them from seeking the death penalty against Luigi Mangione in the 2024 killing of UnitedHealthcare CEO Brian Thompson. In a letter, the government said it would not pursue an "interlocutory review" of the order from U.S. District Judge Margaret M. Garnett, who instructed prosecutors to determine by Friday whether they would appeal her ruling. Mangione's legal team on Friday declined to comment on the government's update. Last month, Garnett dismissed two of the four federal counts against Mangione, 27, which include murder through the use of a firearm and a related firearms offense. That murder charge carries a potential death sentence. Mangione still faces two counts of interstate stalking, which carry a maximum sentence of life in prison without parole. He has pleaded not guilty to the charges.…