feat(chat)!: change safe_prompt, temperature & top_p to non-Option types

BREAKING CHANGE:
- `Chat::ChatParams.safe_prompt` & `Chat::ChatRequest.safe_prompt` are now `bool` instead of `Option<bool>`. Default is `false`.
- `Chat::ChatParams.temperature` & `Chat::ChatRequest.temperature` are now `f32` instead of `Option<f32>`. Default is `0.7`.
- `Chat::ChatParams.top_p` & `Chat::ChatRequest.top_p` are now `f32` instead of `Option<f32>`. Default is `1.0`.

examples/chat_with_function_calling.rs

@@ -53,7 +53,7 @@ fn main() {
         tool_calls: None,
     }];
     let options = ChatParams {
-        temperature: Some(0.0),
+        temperature: 0.0,
         random_seed: Some(42),
         tool_choice: Some(ToolChoice::Auto),
         tools: Some(tools),