By Daniel Bates Forget bulletin board material, Nets guard Bruce Brown gave the Celtics jumbotron material ahead of Sunday’s Game 1. Prior to tip-off, the the Celtics put up Brown’s recent comments going into the Boston series, saying that they aren’t the same team without center Robert Williams III: They don’t have Robert Williams, so they have less of a presence in the pant, and we could attack Al Horford and Theis. So them not having Robert Williams is huge. The Celtics pregame scoreboard quickly went viral. “Thank you Bruce!” tweeted one fan. “I like it,” laughed another user. “Cringe.” “I…