Function function_call_output_content_items_to_text 

pub fn function_call_output_content_items_to_text(
    content_items: &[FunctionCallOutputContentItem],
) -> Option<String>

Converts structured function-call output content into plain text for human-readable surfaces.

This conversion is intentionally lossy:

• only input_text items are included
• image items are ignored

We use this helper where callers still need a string representation (for example telemetry previews or legacy string-only output paths) while keeping the original multimodal content_items as the authoritative payload sent to the model.