A standards album by a former rapper? How ambitious. Or, in this case, ambitiously boring. Latifah, a.k.a. Dana Owens, demanded (and deserved) attention back in her unvarnished ''Ladies First'' days. But with her music now reflecting her Everywoman tastes for mainstream movies and Cover Girl, her flava is fading faster than a Pizza Hut voice-over. She and Al Green smolder in the taut ''Simply Beautiful,'' but the rest of The Dana Owens Album is a smooth-jazz exercise in ordinariness.