fix: webpack + React 17 won't build because of named imports of React 18 APIs

[haivuw]

Fixes #8931 (Reopen since /remixing is deleted)
In current build, rollup outputs these named exports: useSyncExternalStore, startTransition from React. If the user's React version doesn't export them, Webpack won't build:

ERROR in ./node_modules/react-router/index.js 61:10-25
export 'startTransition' (imported as 'startTransition') was not found in 'react'

This fix prevents rollup from outputting these named imports.
node_modules/react-router/index.js:

//before
import { startTransition, useSyncExternalStore as useSyncExternalStore$3, createContext, useContext, useMemo, useRef, useEffect as useEffect$1, useCallback, createElement, Fragment, Component, useState as useState$1, useLayoutEffect as useLayoutEffect$1, Children, isValidElement } from 'react';

//after
import { createContext, useContext, useMemo, useRef, useEffect as useEffect$1, useCallback, createElement, Fragment, Component, useState as useState$1, useLayoutEffect as useLayoutEffect$1, Children, isValidElement } from 'react';

https://rollupjs.org/guide/en/#outputinterop
https://github.dev/webpack/webpack/blob/f9e6b682aba059d13aa3e170ac42b7a797a0ef3f/lib/dependencies/HarmonyImportDependency.js#L141

[brophdawg11]

Interesting - thanks for the PR! We'd ideally use the use-sync-external-store shim directly but it causes some module build issues for us at the moment so we had to pull it in. facebook/react#24590