[Feature Request]: Improve Concatenated Send Messages Logic

### Problem Description

The current concatenated send messages logic has an issue. It only works consistently for `OpenAI`, but when using another provider such as `Anthropic (Claude)`, it does not work consistently.


### Solution Description

If possible, it would be better to improve the logic and make it more structured. The suggested approach is:

1. If there is no `system` role, make the `user` role the first one.
2. If there is a `system` role, make the `user` role the second one.

This improvement would ensure consistent behavior across different providers and a more structured approach to handling concatenated messages.

### Alternatives Considered

_No response_

### Additional Context

_No response_