A top donor to Donald Trump and other Maga Republicans has privately mocked the US president’s longtime position that he has an upper hand in trade negotiations with China, in a sign that even some loyal supporters have been uneasy with the White House strategy. Liz Uihlein, the billionaire businesswoman who co-founded the office supply company Uline with her husband, Richard, sent an email to her staff earlier this year that contained a cartoon in which Trump can be seen playing cards with the Chinese president, Xi Jinping. In the…