Decode log error message (#602)

Decode log error messages which begin with the char 'b' as the mark of byte string.s So that escape chars within messages can work well and can be printed out by a clear format.

feathr_project/feathr/spark_provider/_synapse_submission.py

@@ -178,7 +178,7 @@ def wait_for_completion(self, timeout_seconds: Optional[float]) -> bool:
                 return True
             elif status in {LivyStates.ERROR.value, LivyStates.DEAD.value, LivyStates.KILLED.value}:
                 logger.error("Feathr job has failed.")
-                logger.error(self._api.get_driver_log(self.current_job_info.id))
+                logger.error(self._api.get_driver_log(self.current_job_info.id).decode('utf-8'))
                 return False
             else:
                 time.sleep(30)