(Reuters) -A federal judge in Texas on Wednesday partially blocked a U.S. Federal Trade Commission rule from taking effect that would ban agreements commonly signed by workers not to join their employers' rivals or launch competing businesses. U.S. District Judge Ada Brown in Dallas said in a written decision the FTC, which enforces federal antitrust laws, lacked the power to adopt broad rules prohibiting practices that it deems unfair methods of competition. About 30 million people, or 20% o...