Fix: External redirect swallowed by Next.js (#87121)
Fix for a regression introduced by
https://github.com/vercel/next.js/pull/86367.
When a Server Action performed an external redirect, Next.js was no
longer triggering an MPA navigation from directly inside the response
handler. It would end up working regardless if the Server Action was
called from a React action, like a form action or useTransition hook,
because the Server Action would rethrow the redirect error and trigger a
"late" redirect during rendering. But if the Server Action was called
from outside of a React scope — onClick, for example — it would do
nothing.
