Use shorter responses and configuration for specs

By simplyfing the responses the configuration for specs can be simpler too.

We're also using more generic terms instead of the ones used in Madrid's
Census API.

Co-Authored-By: Javi Martín <javim@elretirao.net>

spec/lib/census_caller_spec.rb

@@ -45,6 +45,9 @@ describe CensusCaller do
     end
 
     describe "RemoteCensusApi", :remote_census do
+      let(:valid_body) { { response: { data: { document_number: "12345678" }}} }
+      let(:invalid_body) { { response: { data: {}}} }
+
       it "returns remote census api response when it's available and response is valid" do
         remote_census_api_response = RemoteCensusApi::Response.new(valid_body)
         allow_any_instance_of(RemoteCensusApi).to receive(:call).and_return(remote_census_api_response)