A self-proclaimed “Grand Sheik” of a Moorish temple who pleaded guilty to stealing $3 million from the federal government  will remain imprisoned after a federal appeals court affirmed his sentence.Marcel A. Walton filed three fraudulent tax returns seeking $900,000 in refunds from the Internal Revenue Service. The IRS sent him back more than $300,000. He also recruited homeless people to join a Chicago branch of the Moorish Science Temple of America by telling them they were entitled to compensation …