Very likely no license can restrict it, since learning is not covered under copyright. Even if you could restrict it, you couldn't add a "no LLMs" clause without violating the free software principles or the OSI definition, since you cannot discriminate in your license.
"Learning" is what humans can do. LLMs can't do that.
“Learning” as a concept is too ill defined to use as a distinction. What is learning? How is what a human does different from what an LLM does?
In the end it doesn’t matter. Here “learning” means observing an existing work and using it to produce something that is not a copy.