add response id for streaming response

[GDaamn]

Further changes for #2663

• Add provider_response_id as an additional property to streamed responses.
• Added this as part of ModelResponse for OpenAIResponsesStreamedResponse and OpenAIStreamedResponse

[DouweM]

Can you please add a test for this?

[GDaamn]

where would you suggest to add this ?
here maybe ?

pydantic-ai/pydantic_ai_slim/pydantic_ai/models/test.py

Lines 281 to 288 in 3b7f299

	class TestStreamedResponse(StreamedResponse):
	"""A structured response that streams test data."""
	_model_name: str
	_structured_response: ModelResponse
	_messages: InitVar[Iterable[ModelMessage]]
	_provider_name: str
	_timestamp: datetime = field(default_factory=_utils.now_utc, init=False)

and subsequently reflect it in https://github.com/pydantic/pydantic-ai/blob/main/tests/test_streaming.py ?

[GDaamn]

created a new PR as uv.lock was causing issues: #2782