fix: astro:config types tests (#13391)

Author: florian-lefebvre

packages/astro/test/types/astro-config-virtual-module.ts

@@ -3,10 +3,11 @@ import { expectTypeOf } from 'expect-type';
 import type {
 	ClientDeserializedManifest,
 	ServerDeserializedManifest,
-} from '../../dist/types/public';
+} from '../../dist/types/public/index.js';
+import '../../client.d.ts';
 
-const server = null as typeof import('astro:config/server');
-const client = null as typeof import('astro:config/client');
+const server = null as unknown as typeof import('astro:config/server');
+const client = null as unknown as typeof import('astro:config/client');
 
 describe('astro:config', () => {
 	it('astro:config/server', () => {