system prompt for o3-mini

[tf-koichi]

Unlike other models, the "role" for a system prompt for o3-mini should be "developer". Right now it is hard coded as "system".

[KennyVaneetvelde]

@tf-koichi I have researched this and apparently, they only made it possible but not required - also it does not seem to have any effect on the output - so for now I'll close this with a won't-fix unless a clear issue arises (Myself and other users have successfully used o3-mini with atomic-agents)