Microsoft CEO Satya Nadella, right, speaks as OpenAI CEO Sam Altman looks on during the OpenAI DevDay event in San Francisco on Nov. 6, 2023. Justin Sullivan | Getty Images Elon Musk's courtroom battle with Sam Altman over the last couple weeks has primarily revolved around the evolution of OpenAI. But it's also shined a light on the challenges that the rapid growth of artificial intelligence caused OpenAI's closest partner: Microsoft . Discovery in the high-profile case showed that Microsoft CEO Satya Nadella was worried about OpenAI supplanting his company in the tech hierarchy as far back as April 2022, seven months before the launch of ChatGPT, the event that kicked off the generative AI boom and turned Altman into a household name. "I don't want to be IBM and OpenAI to be Microsoft," Nadella wrote in a email to executives that April, roughly three years after Microsoft wrote its first $1 billion check to OpenAI.…