fix: add null directly to Ref generic

packages/nuxt/src/app/composables/cookie.ts

@@ -15,9 +15,7 @@ export interface CookieOptions<T = any> extends _CookieOptions {
   default?: () => T | Ref<T>
 }
 
-export interface CookieRef<T> extends Ref<T> {
-  value: T | null | undefined;
-}
+export interface CookieRef<T> extends Ref<T | null> {}
 
 const CookieDefaults: CookieOptions<any> = {
   path: '/',