Updating interactive walkthrough link in index.md to resolve 404 error (#9063)

Updated interactive walkthrough link in index.md to resolve 404 error.
Also, expressing deep gratitude to LangChain library developers for
their exceptional efforts 🥇 .

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

docs/docs_skeleton/docs/guides/langsmith/index.md

@@ -5,8 +5,8 @@ import DocCardList from "@theme/DocCardList";
 LangSmith helps you trace and evaluate your language model applications and intelligent agents to help you
 move from prototype to production.
 
-Check out the [interactive walkthrough](walkthrough) below to get started.
+Check out the [interactive walkthrough](/docs/guides/langsmith/walkthrough) below to get started.
 
 For more information, please refer to the [LangSmith documentation](https://docs.smith.langchain.com/)
 
-<DocCardList />
+<DocCardList />