A lobbying firm led by one of Donald Trump Jnr’s hunting buddies helped a Chinese company make its case to a US national security watchdog, public filings show.The case involved a US start-up that was seeking to have the Chinese firm removed as one of its investors. The watchdog rejected the US firm’s request for a national security review of the Chinese firm’s investment, according to a document seen by Reuters, handing a rare win to a Chinese company in Washington. The decision has not...