Representation of Tether stablecoin cryptocurrency in this illustration taken September 10, 2025. REUTERS/Dado Ruvic/Illustration Purchase Licensing Rights, opens new tabPARIS, Feb 27 (Reuters) - El Salvador-based stablecoin issuer Tether said it has frozen about $4.2 billion of its crypto tokens over links to "illicit activity", mostly in the past three years, as authorities around the world try to crack down on crypto-related crime.The world's largest stablecoin company, which has more than $1...