[BUG] mis-order of strutured_output_span

[chengweitsai]

I think the order does matter, to align what actually sent to model.structured_output. System_prompt will be put at the front of input_messages

sdk-python/src/strands/models/openai.py

Line 186 in cfcf93d

formatted_messages = [{"role": "system", "content": system_prompt}] if system_prompt else []

Originally posted by @chengweitsai in #655 (comment)