Update spec

spec/requests/api/btcpay_spec.rb

@@ -69,7 +69,7 @@ RSpec.describe "/api/btcpay", type: :request do
       expect(response).to have_http_status(:ok)
 
       res = JSON.parse(response.body)
-      expect(res["balance"]).to eq(4200000)
+      expect(res["confirmed_balance"]).to eq(4200000)
     end
 
     context "upstream request error" do