The Abu Dhabi royal family is to take a stake in TikTok’s US business after Donald Trump signed an executive order brokering a deal valuing the social media company at $14bn (£10.5bn).MGX, a fund chaired by Sheikh Tahnoon bin Zayed Al Nahyan, will take a 15% stake and gain a board seat when TikTok US is spun out.The US president signed an executive order on Thursday night approving the deal and providing a 120-day window to finalise the details.Larry Ellison’s Oracle, the private equity group Si...