test: Integration tests for handleNewBooking (#11044)

Co-authored-by: Shivam Kalra <shivamkalra98@gmail.com>
Co-authored-by: Joe Au-Yeung <65426560+joeauyeung@users.noreply.github.com>

setupVitest.ts

@@ -0,0 +1,7 @@
+import { vi } from "vitest";
+import createFetchMock from "vitest-fetch-mock";
+
+const fetchMocker = createFetchMock(vi);
+
+// sets globalThis.fetch and globalThis.fetchMock to our mocked version
+fetchMocker.enableMocks();