Update SimpleQAEval to use direct CSV URL instead of blobfile

[ZhangYiqun018]

Update SimpleQAEval to use direct CSV URL instead of blobfile

Changes made:

• Replace Azure blob storage path (az://) with direct HTTPS URL for accessing the SimpleQA dataset
• Remove blobfile dependency as it's no longer needed
• Use pandas.read_csv() to directly fetch the dataset

The modified URL will be:
https://openaipublic.blob.core.windows.net/simple-evals/simple_qa_test_set.csv

This change simplifies the data loading process and removes the need for Azure blob storage authentication.

Related to issue: #25