fix: add missing blank line between _get_model_name and _should_persist_stream_items (ruff E302)

Author: Aditya Singh

src/agents/run_internal/run_loop.py

@@ -243,6 +243,8 @@ def _get_model_name(model: Any) -> str | None:
     if isinstance(model_name, str):
         return model_name
     return None
+
+
 async def _should_persist_stream_items(
     *,
     session: Session | None,