Revert "Fix Activity sandboxes (#8035)"

This reverts commit f9fd07c.

Author: gaearon

src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md

@@ -11542,7 +11542,7 @@ Try searching for a video, selecting it, and clicking "back":
 <Sandpack>
 
 ```js src/App.js
-import { unstable_ViewTransition as ViewTransition } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router";  import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { unstable_ViewTransition as ViewTransition, Activity } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router";
 
 export default function App() {
   const { url } = useRouter();
@@ -12879,7 +12879,7 @@ With this update, if the content on the next page has time to pre-render, it wil
 <Sandpack>
 
 ```js src/App.js
-import { unstable_ViewTransition as ViewTransition, use } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router"; import {fetchVideos} from './data';  import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { unstable_ViewTransition as ViewTransition, Activity, use } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router"; import {fetchVideos} from './data'
 
 export default function App() {
   const { url } = useRouter();

src/content/reference/react/Activity.md

@@ -206,8 +206,7 @@ and check out the new behavior:
 <Sandpack>
 
 ```js src/App.js active
-import { useState } from 'react'; import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
-
+import { Activity, useState } from 'react';
 import Sidebar from './Sidebar.js';
 
 export default function App() {
@@ -426,7 +425,7 @@ If we switch to using an Activity boundary to show and hide the active tab, we c
 <Sandpack>
 
 ```js src/App.js active
-import { useState } from 'react'; import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { useState, Activity } from 'react';
 import TabButton from './TabButton.js';
 import Home from './Home.js';
 import Contact from './Contact.js';
@@ -704,7 +703,7 @@ Try clicking the Posts tab now:
 <Sandpack>
 
 ```js src/App.js
-import { useState, Suspense } from 'react';  import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { useState, Suspense, Activity } from 'react';
 import TabButton from './TabButton.js';
 import Home from './Home.js';
 import Posts from './Posts.js';
@@ -1128,7 +1127,7 @@ Let's update `App` to hide the inactive tab with a hidden Activity boundary inst
 <Sandpack>
 
 ```js src/App.js active
-import { useState } from 'react'; import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { useState, Activity } from 'react';
 import TabButton from './TabButton.js';
 import Home from './Home.js';
 import Video from './Video.js';
@@ -1262,7 +1261,7 @@ Let's see the new behavior. Try playing the video, switching to the Home tab, th
 <Sandpack>
 
 ```js src/App.js active
-import { useState } from 'react';  import { unstable_Activity, Activity as ActivityStable} from 'react'; let Activity = ActivityStable ?? unstable_Activity;
+import { useState, Activity } from 'react';
 import TabButton from './TabButton.js';
 import Home from './Home.js';
 import Video from './Video.js';