fix: code node garbled in Javascript (#4615)

api/core/helper/code_executor/javascript/javascript_transformer.py

             {cls._code_placeholder}
             
             // decode and prepare input object
-            var inputs_obj = JSON.parse(atob('{cls._inputs_placeholder}'))
+            var inputs_obj = JSON.parse(Buffer.from('{cls._inputs_placeholder}', 'base64').toString('utf-8'))
             
             // execute main function
             var output_obj = main(inputs_obj)