fix(decorators): stack trace on failed auth_check (#961)

Author: hassiebp

langfuse/decorators/langfuse_decorator.py

@@ -1110,7 +1110,9 @@ def auth_check(self) -> bool:
         try:
             return self.client_instance.auth_check()
         except Exception as e:
-            self._log.error("No Langfuse object found in the current context", e)
+            self._log.error(
+                "No Langfuse object found in the current context", exc_info=e
+            )
 
             return False