PHILADELPHIA — The Philadelphia Art Commission has voted unanimously to give final approval to the concept and design for the new Harriet Tubman statue proposed by sculptor Alvin Pettit. On Wednesday, Art Commission members, who praised Pettit’s presentation for its ideas, voted unanimously to approve the design of the statue after just one meeting to discuss it. Seven members of the commission were present. The commission’s website lists nine members. Pettit is a Jersey City, New Jersey-based sculptor whose statue design, “A Higher Power: The Call of a Freedom Fighter,” was selected from five…