test(responses): restore patch import lost in cleanup

I found test_acompletion_bridge_normalizes_stream_options_on_the_wire
failing with NameError: name 'patch' is not defined. An earlier
unused-imports cleanup on this branch dropped patch from the
unittest.mock import line even though two tests still call
patch.object(...). I added patch back, plus MagicMock and the httpx
import that the same tests need, and left ANY out since nothing in
the file uses it anymore.

All 71 tests in this file pass again.

tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py

@@ -1,8 +1,9 @@
 import json
 import os
 import sys
-from unittest.mock import Mock
+from unittest.mock import MagicMock, Mock, patch
 
+import httpx
 import pytest
 
 sys.path.insert(