Improve FAPI error handling

[dimitrystd]

Tried to upload file, but FAPI returned error. As result i got error in SDK instead of the original error

Response code: 0 
Response message: Bad response format from Smartling 
Response trace: #0 /usr/share/nginx/dreamtrips/vendor/smartling/api-sdk-php/src/BaseApiAbstract.php(321): Smartling\BaseApiAbstract->processError(Object(GuzzleHttp\Message\Response)) 
#1 /usr/share/nginx/dreamtrips/vendor/smartling/api-sdk-php/src/BaseApiAbstract.php(500): Smartling\BaseApiAbstract->processErrors(Object(GuzzleHttp\Message\Response)) 
#2 /usr/share/nginx/dreamtrips/vendor/smartling/api-sdk-php/src/File/FileApi.php(82): Smartling\BaseApiAbstract->sendRequest('file', Array, 'post') 
#3 /usr/share/nginx/dreamtrips/app/Services/Translator/SmartlingApi.php(82): Smartling\File\FileApi->uploadFile('data://text/pla...', 'errors.json', 'json')

FAPI error was

{
  "response": {
    "code": "GENERAL_ERROR",
    "messages": [
      "An error has occurred and administrators have been notified. For more information, please contact <a href=\"mailto:support@smartling.com\">support@smartling.com</a> with reference code \"j5meo4yt\"."
    ],
    "data": null
  }
}

DoD:

• SDK can handle not only sussess FAPI responses buy error responses too
• Cover this case with unit test