bug/<partition returns empty output and exits with code 0>

Describe the bug

When using the partition function from unstructured.partition.auto to process a PDF file (embedded-images.pdf), the program finishes execution with exit code 0 but produces no output. Expected behavior is to see extracted content printed, but there's nothing returned.

To Reproduce

code:

from unstructured.partition.auto import partition

elements = partition("./example-docs/pdf/embedded-images.pdf")
print("\n\n".join([str(el) for el in elements]))

Ensure the ./example-docs/pdf/embedded-images.pdf file exists and is accessible.
Run the script. Observe that there's no output, and the process exits with code 0.

Expected behavior

The partition function should extract content (text, image metadata, etc.) from the PDF and the print statement should output the joined string representation of the extracted elements, showing relevant information like text blocks, image details, etc.

Additional context
Tried with different PDF files (simple text-only PDFs, other PDFs with images) and got the same silent exit with code 0 result in some cases, which makes me think there might be an issue with the partition function's handling of certain PDF structures or a potential bug in the auto-partition logic.

Run the provided reproduction with example-docs/pdf/embedded-images.pdf and inspect the unstructured.partition.auto.partition entry point to trace how the PDF is handled. Compare the result with text-only and image-containing PDFs; done means the example produces the expected extracted elements instead of silently returning no output.