A 23-year-old man was arrested last week after he claimed to be a Federal Trade Commission agent and collected $900,000 in gold coins from a Trumbull resident, police said. Tushar Sharma, who is from India but currently lives in Arcadia, California, was arrested on Thursday by the Trumbull Police Department Detective Bureau and Crime Suppression Unit and the Bridgeport Police Department Task Force. He was charged with conspiracy to commit larcen…