By Madeline Coleman The Stewart-Haas Racing driver appeared to slow down in front of competitors on the final lap of Sunday’s race, helping his teammate advance in the playoffs. NASCAR has dealt a hefty penalty to Cole Custer, Stewart-Haas Racing and the No. 41 car crew chief, Michael Shiplett, after Sunday’s playoff race in Charlotte. Custer appeared to slow down on the final lap, directly into the path of Austin Dillon and Erik Jones. The move allowed Custer’s teammate, Chase Briscoe, to slip through and eventually secure a spot in the next round of the playoffs by a two-point margin. Meanti…