fix(tracing): convert tool schema dump from python to json

Author: yaozheng-fang

veadk/tracing/telemetry/attributes/extractors/llm_attributes_extractors.py

@@ -529,8 +529,8 @@ def llm_gen_ai_request_functions(params: LLMAttributesParams) -> ExtractorRespon
                 f"gen_ai.request.functions.{idx}.description": tool_instance.description,
                 f"gen_ai.request.functions.{idx}.parameters": str(
                     tool_instance._get_declaration().parameters.model_dump(  # type: ignore
-                        exclude_none=True
-                    )
+                        exclude_none=True, mode="json"
+                    )  # use `json` mode to flatten Enum class. e.g., from `Type.STRING` to `STRING`
                     if tool_instance._get_declaration()
                     and tool_instance._get_declaration().parameters  # type: ignore
                     else {}