update litellm to use Responses API for Openai models

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please update litellm to use the responses api . we cant see the thought summaries with chat completions

### Is your feature request related to a specific problem?
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when I have to manually handle X...")

we cant see the thought summaries with chat completions

### Describe the Solution You'd Like
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use responses api

### Impact on your work
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this feature.

important for eval . had to monkey patch

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## 🟡 Recommended Information

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### Additional Context
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