I should have some say over how my actual voice is used. If I am a public figure, ala Donald Trump, and there are a lot of people out there who do a great impression of me, those voices belong to the people actually creating them, not me.
If it turns out that there are people out there who either naturally sound like Scarlett Johansson, or who can alter their voice so that they sound like her, they should have the freedom to profit from their own talents (natural or otherwise).
If the resulting AI voice isn't actually claiming to be Johansson and isn't trained using her actual voice, I don't see anything wrong with it.