People do celebrity impressions all the time, and that's not infringement either, because it's not actually copying that person's voice.
I'm sympathetic to SJ in this matter, especially after the Disney Black Widow debacle, but it sounds like she had the opportunity to write herself a nice check, and she turned it down.
On the basis of this article, it sounds like she doesn't have the cause of action that she had believed she had; I imagine that her legal team are now advising a fast settlement, but OpenAI's legal team might prefer to milk the free publicity for as long as they can, especially if they are fairly certain they would prevail at trial.
If I were SJ, I'd turn it down too. Shes in no need of money, and selling her voice to OpenAI would make most of creators and every single voice actor hate her (not to mention the Twitter mob).
In majority of creative circles, the current social norm is to hate AI, so touching AI in any way is too risky for reputation.