(Adds report of Robinhood drawing down some credit lines) Jan 28 (Reuters) - An army of retail investors that has routed Wall Street’s professionals in recent days was dealt a blow on Thursday, after online brokerages restricted purchases of red-hot GameStop and other stocks that had soared this week. But the shares rebounded in after hours trading, resuming their advances after Robinhood Markets Inc and Interactive Brokers said they planned to lift the restrictions on Friday. Retail investors, celebrities and policymakers had denounced Thursday’s restrictions and participants in online f...