Fix client `fetch_token` throwing `NoMethodError` when raise_errors is set to false
Created by: joaolrpaulo
The problem occurs when the identifier service is unreachable and we are passing the :raise_errors option set to false.
The fetch_token method throws NoMethodError while trying to perform the following code:
response.parsed.merge(access_token_opts)
This happens because the response.parsed is nil.