refactor: extract agent_connect logout_url to a agent_connect_service

spec/services/agent_connect_service_spec.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+describe AgentConnectService do
+  describe '.logout_url' do
+    let(:id_token) { 'id_token' }
+
+    before do
+      ::AGENT_CONNECT ||= {}
+      allow(AGENT_CONNECT).to receive(:[])
+        .with(:end_session_endpoint).and_return("https://agent-connect.fr/logout")
+    end
+
+    subject { described_class.logout_url(id_token, host_with_port: 'test.host') }
+
+    it 'returns the correct url' do
+      expect(subject).to eq("https://agent-connect.fr/logout?id_token_hint=id_token&post_logout_redirect_uri=http%3A%2F%2Ftest.host%2Flogout")
+    end
+  end
+end