docs: update how_to docs to reflect new loaders interface and functionalities (#31219)

- **Description:** Updates two notebooks in the how_to documentation to
reflect new loader interfaces and functionalities.
- **Issue:** Some how_to notebooks were still using loader interfaces
from previous versions of LangChain and did not demonstrate the latest
loader functionalities (e.g., extracting images with `ImageBlobParser`,
extracting tables in specific output formats, parsing documents using
Vision-Language Models with `ZeroxPDFLoader`, and using
`CloudBlobLoader` in the `GenericLoader`, etc.).
- **Dependencies:** `py-zerox`
- **Twitter handle:** @MarcMedlock2

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Co-authored-by: Marc Medlock <marc.medlock@octo.com>
Co-authored-by: Chester Curme <chester.curme@gmail.com>

Author: 3 people