Upgrade from langchain.document_loaders to langchain_unstructured

[antonum]

https://github.com/redis-developer/redis-ai-resources/blob/main/python-recipes/RAG/01_redisvl.ipynb

loader = UnstructuredFileLoader(
    doc, mode="single", strategy="fast"
)

Fails to load any data and triggers the warning:

:8: LangChainDeprecationWarning: The class UnstructuredFileLoader was deprecated in LangChain 0.2.8 and will be removed in 1.0. An updated version of the class exists in the :class:~langchain-unstructured package and should be used instead. To use it run pip install -U :class:~langchain-unstructured and import as from :class:~langchain_unstructured import UnstructuredLoader``.
loader = UnstructuredFileLoader(
Done preprocessing. Created 0 chunks of the original pdf resources/nke-10k-2023.pdf