Jem Aswad Senior Music EditorKendrick Lamar dropped his first new solo single in nearly four years on Sunday night, called “The Heart Part 5.” The song arrives just days before the long-awaited release of his fifth solo album, “Mr. Morale & the Big Steppers” on May 13.The song’s video begins with Lamar rapping by himself in front of a red screen, but occasionally has the faces of other rappers and controversial public figures photoshopped over his: Kanye West, Nipsey Hussle, Will Smith, Kobe Bryant, OJ Simpson and Jussie Smollett are six that we noticed after one screening. Lamar unveiled the long-awaited “Mr.