[BUG][GO service]Return to 500 if number is single digit on GET /formatting/number/localizedNumber API.

[lyiyu66]

Describe the bug
commit:3c64756c205b147b882f64f01f171e4a90ed8ae0
Return to 500 if number is single digit on GET /formatting/number/localizedNumber API.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'GET /formatting/number/localizedNumber' API.
2. Input "en" and "-5.01" as locale and number parameters' values.
3. See error
   

Expected behavior
Return to 200 and display correct value:

{
  "response": {
    "code": 200,
    "message": "OK",
    "serverTime": ""
  },
  "signature": "",
  "data": {
    "number": "-5.01",
    "formattedNumber": "-5",
    "scale": "0",
    "locale": "en"
  }
}