fix: remove unused imports from test file

Author: giulio-leone

tests/test_response_event_logprobs.py

@@ -4,9 +4,7 @@
 Non-OpenAI providers may not include logprobs in streaming responses.
 """
 
-import pytest
-
-from openai.types.responses.response_text_delta_event import ResponseTextDeltaEvent, Logprob
+from openai.types.responses.response_text_delta_event import ResponseTextDeltaEvent
 from openai.types.responses.response_text_done_event import ResponseTextDoneEvent