fix: add python-multipart required by FastAPI form parsing

Author: bharghavaram

requirements.txt

@@ -10,6 +10,7 @@ pydantic==2.9.2
 python-dotenv==1.0.1
 tiktoken==0.7.0
 numpy==1.26.4
+python-multipart==0.0.12
 httpx==0.27.2
 pytest==8.3.3
 pytest-asyncio==0.24.0