fix: update import path for Router in unit tests

Author: arnabrahman

packages/event-handler/tests/unit/appsync-graphql/Router.test.ts

@@ -1,5 +1,5 @@
-import { Router } from 'src/appsync-graphql/Router.js';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { Router } from '../../../src/appsync-graphql/Router.js';
 
 describe('Class: Router', () => {
   beforeEach(() => {