Updating format of pip install (#19198)

Thank you for contributing to LangChain!

- [x] **PR title**: "Updating format of pip install in two files of
docs/cookbook"
- pip install is not reflecting properly in some of the files in
cookbook
- Example:
[docs/expression_language/cookbook/sql_db](https://python.langchain.com/docs/expression_language/cookbook/sql_db)


- [x] **PR message**: Updating format of pip install in two files of
docs/cookbook
    - **Description:** a description of the change
    - **Issue:** #19197 

- Note - let's do squash merge for the PR

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, hwchase17.

docs/docs/expression_language/cookbook/multiple_chains.ipynb

@@ -20,9 +20,11 @@
    ]
   },
   {
-   "cell_type": "raw",
+   "cell_type": "code",
    "id": "0f316b5c",
+   "execution_count": null,
    "metadata": {},
+   "outputs": [],
    "source": [
     "%pip install --upgrade --quiet  langchain langchain-openai"
    ]

docs/docs/expression_language/cookbook/sql_db.ipynb

@@ -20,9 +20,11 @@
    ]
   },
   {
-   "cell_type": "raw",
+   "cell_type": "code",
    "id": "b3121aa8",
+   "execution_count": null,
    "metadata": {},
+   "outputs": [],
    "source": [
     "%pip install --upgrade --quiet  langchain langchain-openai"
    ]