Move Ably sandbox code to test/lib

I’ll reuse it in the upcoming integration tests.

Author: lawrence-forooghian

test/cdn-bundle/test/cdnBundle.test.ts

@@ -1,5 +1,5 @@
 import { test, expect } from '@playwright/test';
-import { createSandboxAblyAPIKey } from '../lib/ablySandbox.js';
+import { createSandboxAblyAPIKey } from '../../lib/ablySandbox.js';
 
 test.describe('CDN bundle', () => {
   /**

test/cdn-bundle/lib/ablySandbox.ts renamed to test/lib/ablySandbox.ts

@@ -1,5 +1,5 @@
 import https from 'node:https';
-import testAppSetup from '../../ably-common/test-resources/test-app-setup.json';
+import testAppSetup from '../ably-common/test-resources/test-app-setup.json';
 
 export interface TestApp {
   keys: TestAppKey[];

test/lib/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "resolveJsonModule": true
+  }
+}