Bruno Mars, from left, Dernst Emile II and Anderson .Paak accept the Song of the Year award for “Leave the Door Open” at the 64th Grammy Awards. (Rich Fury / Getty Images for the Recording Academy) *Anderson .Paak has worked with two of music’s most meticulous producers, and he says Bruno Mars takes perfectionism to another level. During an appearance on Dhar Mann’s “What Happens Next” podcast, .Paak described Mars and Dr. Dre as “neck and neck”…