When the API returns 404 Sandbox not found, the page shows a Loading skeleton forever.

🐛 bug report

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project
  adheres to.
• I have searched the issue tracker for an issue that matches the one I want
  to file, without success.

Description of the problem

Console shows 404 on the following API URL:

https://codesandbox.io/api/v1/sandboxes/lexical-plain-text-example-g932e

When the API returns the following response with an HTTP 404 status,

{
    "error": "Sandbox not found"
}

the Codesandbox website gets stuck showing "Loading" screen forever.

How has this issue affected you? What are you trying to accomplish?

Trying to view Lexical example. Apparently the sandbox is deleted or something, but Codesandbox just shows a Loading skeleton forever, which is confusing at first glance.

It should show "This sandbox doesn't exist." or a similar message. Additional elements like a link to the home page, a "Create a new sandbox" button or a list of suggested sandboxes are up to you.

To Reproduce

Try this publicly linked Lexical Plain Text Sandbox from the Lexical docs page here. Or try the link to any sandbox that was removed.

Link to sandbox: link (optional)

Your Environment

Reproduce the issue using the linked Lexical Plain Text Sandbox and inspect the frontend request handling for the /api/v1/sandboxes/lexical-plain-text-example-g932e 404 response. The work is done when a missing sandbox displays a clear message such as "This sandbox doesn't exist" instead of remaining on the Loading skeleton.