Same purpose as #48297, but without the React channel branching logic to
make it easier to land. Since we have #48478 reverted, we only need to
consider `pages` and `app` inside the require hook.
> This PR aims to improve the current require hook by implementing two
key changes. Firstly, it ensures that the initialization occurs at the
top of the module level for correctness. Secondly, we now set the
NEXT_PREBUNDLED_REACT environment variable at the process level to
ensure that we don't mix the two types of rendering processes and we
always resolve the correct React package.
>
> These improvements are made possible by the changes introduced in PR
https://github.com/vercel/next.js/pull/47857.
>
> Closes [NEXT-231](https://linear.app/vercel/issue/NEXT-231).
This will likely fix#45258 too.
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Co-authored-by: JJ Kasper <jj@jjsweb.site>
b5f7f84485