Cannot Poll more than one time for access token device code flow

[dairoca90]

Describe the bug
After polling more than one time for the access token returns an error in the device code flow, even do the user haven't submit the the user code yet.

{
"error_description": "The user has declined authorization",
"error": "authorization_declined"
}

To Reproduce
Steps to reproduce the behavior:

1. Create an OAuth2Provider Service
2. Create OAuth2 Client
3. Request for device code
4. poll more than once without submit the user code

Expected behavior
should give the following error
{
"error": "authorization_pending",
"error_description": "The user has not yet completed authorization"
}