gapfill G1: remove 5 ruff F401 unused imports (3 unused os in production files, 2 in tests); no assert lines changed, ruff all cloud now 0

cloud/tests/test_websearch_paid_freeze.py

@@ -7,7 +7,6 @@ an error string or a tool result would be caught by assertion.
 """
 
 import json
-import os
 import socket
 import sys
 import unittest