refactor: Extract iconUrl generation of steps to helper

packages/backend/src/helpers/generate-icon-url.js

@@ -0,0 +1,7 @@
+import appConfig from '../config/app.js';
+
+export const generateIconUrl = (appKey) => {
+  if (!appKey) return null;
+
+  return `${appConfig.baseUrl}/apps/${appKey}/assets/favicon.svg`;
+};