When OpenAI issued a casting call last year for a secret project to endow OpenAI’s popular ChatGPT with a human voice, the flier had several requests: The actors should be nonunion. They should sound between 25 and 45 years old. And their voices should be “warm, engaging [and] charismatic.”One thing the artificial intelligence company didn’t request, according to interviews with multiple people involved in the process and documents shared by OpenAI in response to questions from The Washington Po...