All the kids got a chance to meet and greet team mascots, Mr. and Mrs. Met. (Photo: Alexandra Moyen) FLUSHING — St. Mel’s Catholic Academy’s graduation celebration was more than a send-off for 11 eighth graders — it was a milestone six years in the making, marking not only the students’ next step to high school but also a major step in the school’s comeback story. “It’s a rebirth of the school,” said Principal Lauren Giacalone, reflecting on wh…