Luis Fonsi is a man of many faces. In his wildly viral video for “Despacito,” the reggaetónero finds him luxuriating in ripe, tropical territory. But he's a balladeer in a rocker's leather jacket in the minimalist setting for “Gritar.” Toggling between playing a lovelorn troubadour and a fly seducer, the urban islander always has surprises in store.