setup_chat_template still used in chapter 11 of the LLM course

In Chapter 11.3 of the [Huggingface LLM course](https://huggingface.co/learn/llm-course/chapter11/3), the code snippet to start fine-tuning the model uses the `setup_chat_template` function which is deprecated and removed from newer versions of the `trl` library.

I have created a pull request with proposed changes updating that snippet to use `clone_chat_template` instead.

Here is the PR link. I would love a review on it. This fix will keep learners from having to track down what the replacement function is. https://github.com/huggingface/course/pull/1167