Mistral AI - Adopt ToolCallingManager API

- Update MistralAiChatModel to use the new ToolCallingManager API, while ensuring full API backward compatibility.
- Introduce Builder to instantiate a new MistralAiChatModel since the number of overloaded constructors is growing too big.
- Update documentation about tool calling and Mistral AI support for that.
- Add extra validation to ensure the uniqueness of tool names when aggregated from different sources.

Signed-off-by: Thomas Vitale <ThomasVitale@users.noreply.github.com>

Author: ThomasVitale