feat: Implement an API endpoint to get flow folder

packages/backend/src/controllers/api/v1/flows/get-folder.js

@@ -0,0 +1,12 @@
+import { renderObject } from '../../../../helpers/renderer.js';
+
+export default async (request, response) => {
+  const flow = await request.currentUser
+    .$relatedQuery('flows')
+    .findOne({ id: request.params.flowId })
+    .throwIfNotFound();
+
+  const folder = await flow.$relatedQuery('folder').throwIfNotFound();
+
+  renderObject(response, folder);
+};