NEW YORK — RJ Barrett has made a three-summer commitment to the Canadian National Team. The Knicks’ budding star was named to his nation’s “core roster” on Tuesday, with the purpose of locking in the 14 players through the Paris Olympics in 2024. Barrett is expected to participate in the World Cup qualifiers beginning July, with Canada among the favorites to qualify for the tournament next summer in Asia (Philippines, Japan, Indonesia). Canada will host Dominican Republic on July 1. It is the first FIBA game in Canada since the start of the pandemic, and, if Barrett plays, it’ll be his first m…