NEW YORK — A Brazilian tourist was stabbed in the neck in an unprovoked attack at the Queens Plaza subway station Thursday morning, cops said. The 29-year-old man was stabbed around 10:30 a.m. as he waited on a platform at the station, which serves the E, M and R trains, police said. Cops were searching for his attacker Thursday. The injured man was taken to Elmhurst Hospital in stable condition, police said. Assaults have jumped in the city’s transit system this year. As of Sunday, 64 assaults were reported in the city’s subway system in 2024, compared to 58 recorded in the same period of 202…