fix(code-quality): RUF005 use iterable unpacking instead of list concatenation

Signed-off-by: chenhany <chenhany@nvidia.com>

Author: ChenhanYu

examples/dataset/conversation_utils.py

@@ -124,7 +124,7 @@ def _augment(example: dict[str, Any], idx: int) -> dict[str, Any]:
                 # Conflict: dataset already has a system prompt — skip this augmentation.
                 pass
             else:
-                messages = [{"role": "system", "content": spec.content}] + messages
+                messages = [{"role": "system", "content": spec.content}, *messages]
 
         return {"messages": messages}