upload_pdf_files does not check for file type or format

[OlegSudakov]

Experimenting with notebooks can create .ipynb_checkpoints folder in RetrievalAugmentedGeneration/notebooks/dataset.

This will cause upload_pdf_files function to fail when increasing NUM_DOCS_TO_UPLOAD. The issue does not occur with default NUM_DOCS_TO_UPLOAD (100), as the number of .pdf files in dataset.zip is greater than 100.

[shubhadeepd]

@OlegSudakov Thanks for pointing this bug out.
This should have been fixed with the latest v0.2.0 release.
https://github.com/NVIDIA/GenerativeAIExamples/blob/main/notebooks/05_dataloader.ipynb
Feel free to close this issue after checking.