[BUG] [GO service]Inconsistent behavior when inputting invalid locale on GET /formatting/number/localizedNumber API between GO and JAVA services.

Describe the bug
commit: 3c64756c205b147b882f64f01f171e4a90ed8ae0
Inconsistent behavior when inputting invalid locale on GET /formatting/number/localizedNumber API between GO and JAVA services.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'GET /formatting/number/localizedNumber' API.
2. Input "abc" as locale parameter's value.
3. See the responses:
   GO service: verify the locale validity

{
  "response": {
    "code": 400,
    "message": "invalid Locale 'abc'"
  }
}

JAVA service: return the en format

{
  "response": {
    "code": 200,
    "message": "OK",
    "serverTime": ""
  },
  "signature": "",
  "data": {
    "number": "567",
    "formattedNumber": "567",
    "scale": "0",
    "locale": "abc"
  }
}

Expected behavior
Should have consistent behavior.