fix: add UTF-8 encoding and ensure_ascii=False for JSON telemetry logs (#1178)

Author: LuneZ99

openhands-sdk/openhands/sdk/llm/utils/telemetry.py

@@ -297,8 +297,8 @@ def log_llm_call(
                 and "tools" in data["kwargs"]
             ):
                 data["kwargs"].pop("tools")
-            with open(fname, "w") as f:
-                f.write(json.dumps(data, default=_safe_json))
+            with open(fname, "w", encoding="utf-8") as f:
+                f.write(json.dumps(data, default=_safe_json, ensure_ascii=False))
         except Exception as e:
             warnings.warn(f"Telemetry logging failed: {e}")