NASHVILLE, Tenn. — The Blues let a 3-0 lead slip away, regained it at 4-3, let that one get away, before Robert Thomas scored his fourth goal in the past two games as the Blues won a Central Division showdown, 7-4, over the Predators on Saturday afternoon at Bridgestone Arena. The Blues entered the game second in the Central Division with a three-point lead on fourth-place Nashville and were one point up on idle Minnesota. Thomas scored his 12th goal of the season, extending his career high, off a pass from Jordan Kyrou with 2:38 to go. Kyrou carried the puck toward the net, then as the defens…