DETROIT — “Full House” star Dave Coulier, who grew up in St. Clair Shores and moved back to his hometown in 2019, is opening up about his struggles with alcohol. In a lengthy post on Instagram Thursday, Coulier, 62, shared a photo of himself with a large, bloody scratch down his face, which he said he got after tripping on stairs. He said he “was a drunk” but he’s now been sober since Jan. 1, 2020. “When I drank, I was the life of the party,” Coulier wrote. “I could make people laugh until they fell down. In this picture I was the one who fell down. Not because I was playing hockey or doing th…