A valued certification for humane animal care awarded to Petco Health & Wellness in March is now under attack by PETA, which contends it amounts to false advertising. The animal rights group, People for the Ethical Treatment of Animals, filed a citizen’s complaint on Tuesday with the U.S. Federal Trade Commission. It seeks an investigation and injunction. “Well-intentioned shoppers are getting duped into buying from Petco,” PETA alleges. The dispute centers on the American Humane Certified Seal of Approval. San Diego-based Petco is the first — and so far only — pet retailer to get the designat…