code fix & added goldens in USCensusPEP_AgeSexRaceHispanicOrigin

[niveditasing]

Python Code Fixes (pep_asrh_download_script.py)

• Bypassed Bot-Blocking: Added headers={"User-Agent": "Mozilla/5.0"} to both requests.head (during URL availability verification) and requests.get (during file downloads).
• Added Polite Delays: Imported time and introduced a time.sleep(1) delay before running sequential HTTP requests, smoothing out traffic peaks and preventing server rate-limiting.

[gemini-code-assist]

Code Review

This pull request introduces validation configurations and golden data files for the US Census PEP ASRH import, including adding a validation_config.json and updating the manifest. Additionally, the download script pep_asrh_download_script.py was updated to include a polite delay and a custom User-Agent header when making requests. The review feedback correctly identifies that the time module is imported locally inside functions and loops, which violates PEP 8 guidelines, and recommends moving the import to the top of the file.