BREAKING CHANGE:
- `Chat::ChatParams.safe_prompt` & `Chat::ChatRequest.safe_prompt` are now `bool` instead of `Option<bool>`. Default is `false`.
- `Chat::ChatParams.temperature` & `Chat::ChatRequest.temperature` are now `f32` instead of `Option<f32>`. Default is `0.7`.
- `Chat::ChatParams.top_p` & `Chat::ChatRequest.top_p` are now `f32` instead of `Option<f32>`. Default is `1.0`.