Fixed when a log decoding error caused the process to terminate. (#515)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Improved error handling when retrieving logs to prevent decoding
errors from causing failures. If a decoding error occurs, an empty log
is returned instead of an error message.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: xiaoyeqiannian

dpdispatcher/utils/dpcloudserver/client.py

@@ -278,7 +278,11 @@ def get_log(self, job_id):
             return ""
         resp = requests.get(url, headers={"Range": f"bytes={self.last_log_offset}-"})
         self.last_log_offset += len(resp.content)
-        return resp.content.decode("utf-8")
+        try:
+            return resp.content.decode("utf-8")
+        except Exception as e:
+            dlog.error(f"Error decoding job log: {e}", stack_info=ENABLE_STACK)
+            return ""
 
     def _get_job_log(self, job_id):
         ret = self.get(