Errors when uploading candidates with peak_map_sigma of nan

[Elle-WANG]

This is the error message for SB77146 beam16, where the peak_map_sigma for J205715.78-410123.62 is nan

"{'peak_map_sigma': [ErrorDetail(string='A valid number is required.', code='invalid')]}"
Traceback (most recent call last):
  File "/fred/oz330/software/vaster_webapp/ywangvaster_webapp/upload_cand.py", line 408, in <module>
    upload_data(args.base_url, args.token, args.project_id, args.observation_id, data_path)
  File "/fred/oz330/software/vaster_webapp/ywangvaster_webapp/upload_cand.py", line 336, in upload_data
    send_cand_request(
  File "/fred/oz330/software/vaster_webapp/ywangvaster_webapp/upload_cand.py", line 273, in send_cand_request
    r.raise_for_status()
  File "/fred/oz002/ywang/apps/miniconda/envs/vaster/lib/python3.9/site-packages/requests/models.py", line 1021, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 400 Client Error: Bad Request for url: http://vaster.duckdns.org:80/upload_candidate/
Traceback (most recent call last):
  File "/fred/oz002/ywang/apps/miniconda/envs/vaster/bin/upload_realtime_candidates", line 33, in <module>
    sys.exit(load_entry_point('vaster', 'console_scripts', 'upload_realtime_candidates')())
  File "/home/yuwang/scripts/vaster_pipeline/src/vaster/upload_realtime_candidates.py", line 146, in _main
    upload_files(args, sbid)
  File "/home/yuwang/scripts/vaster_pipeline/src/vaster/upload_realtime_candidates.py", line 336, in upload_files
    subprocess.run(cmd, check=True)
  File "/fred/oz002/ywang/apps/miniconda/envs/vaster/lib/python3.9/subprocess.py", line 528, in run
    raise CalledProcessError(retcode, process.args,