ChatCompletionStreamOptions.include_obfuscation should be skipped during serialization if none

[codito]

Please consider marking ChatCompletionStreamOptions.include_obfuscation as #[serde(skip_serializing_if = "Option::is_none")]. As per spec (screenshot below), it is optional field.

Including this field even when none breaks the Gemini's OpenAI compatible API.

async-openai version: v0.32.2

[64bit]

Fixed in v0.32.3