Fix breaking changes from openai 1.66.2

Author: rm-openai

src/agents/models/openai_chatcompletions.py

@@ -54,7 +54,7 @@
     ResponseUsage,
 )
 from openai.types.responses.response_input_param import FunctionCallOutput, ItemReference, Message
-from openai.types.responses.response_usage import OutputTokensDetails
+from openai.types.responses.response_usage import InputTokensDetails, OutputTokensDetails
 
 from .. import _debug
 from ..agent_output import AgentOutputSchema
@@ -420,6 +420,11 @@ async def stream_response(
                         and usage.completion_tokens_details.reasoning_tokens
                         else 0
                     ),
+                    input_tokens_details=InputTokensDetails(
+                        cached_tokens=usage.prompt_tokens_details.cached_tokens
+                        if usage.prompt_tokens_details and usage.prompt_tokens_details.cached_tokens
+                        else 0
+                    ),
                 )
                 if usage
                 else None