removed CardLists for LLMs and ChatModels (#12307)
Problem statement:
In the `integrations/llms` and `integrations/chat` pages, we have a
sidebar with ToC, and we also have a ToC at the end of the page.
The ToC at the end of the page is not necessary, and it is confusing
when we mix the index page styles; moreover, it requires manual work.
So, I removed ToC at the end of the page (it was discussed with and
approved by @baskaryan)
