fix(api): show most recent date for FullStack cert (#38736)

api-server/server/boot_tests/certificate.test.js

@@ -0,0 +1,12 @@
+/* global it expect */
+
+import { getFallbackFrontEndDate } from '../boot/certificate';
+import { fullStackChallenges } from './fixtures';
+
+describe('boot/certificate', () => {
+  describe('getFallbackFrontEndDate', () => {
+    it('should return the date of the latest completed challenge', () => {
+      expect(getFallbackFrontEndDate(fullStackChallenges)).toBe(1685210952511);
+    });
+  });
+});