A 7-year-old boy and a 21-year-old woman were injured after being struck by a hit-and-run driver on Halloween in North Plainfield, authorities said. The two were hit around 6:20 p.m. at the intersection of Mountain Avenue and Jeffries Place, North Plainfield police said in a statement. Both the boy and the woman were brought to an area trauma center with injuries, authorities said. Police didn’t immediately describe the extent of the pedestrians’ injuries or offer a description of the vehicle used in the alleged hit-and-run. Police also did not say if the woman and child were trick-or-treating…