Adjust customers api response

ee/app/services/subscriptions/create_service.rb

@@ -98,7 +98,7 @@ module Subscriptions
       Rails.cache.fetch('customers_oauth_app_id', expires_in: 1.hour) do
         response = client.customers_oauth_app_id
 
-        response.dig(:data, 'customers_oauth_app_id')
+        response.dig(:data, 'oauth_app_id')
       end
     end
 

ee/spec/services/subscriptions/create_service_spec.rb

@@ -35,7 +35,7 @@ RSpec.describe Subscriptions::CreateService do
 
   describe '#execute' do
     before do
-      allow(client).to receive(:customers_oauth_app_id).and_return( { data: { 'customers_oauth_app_id' => oauth_app.uid } } )
+      allow(client).to receive(:customers_oauth_app_id).and_return( { data: { 'oauth_app_id' => oauth_app.uid } } )
       allow(Doorkeeper::OAuth::Helpers::UniqueToken).to receive(:generate).and_return('foo_token')
     end