fix: Don't reset shallow URL updates on prefetch (#58297)
## Description
Between 14.0.2-canary.6 and 14.0.2-canary.7, a change was introduced in vercel/next.js#56497 that turned the Redux store state into a Promise, rather than a synchronous state update.
This caused the `sync` function -- used to send state updates to the Redux Devtools -- to be recreated on every dispatch, which in turn, by referential instability, caused the `HistoryUpdater` component to re-render and trigger a `history.replaceState` with no particular change, but with the internal `canonicalUrl`.
When an app does a soft/shallow navigation by calling history methods directly (currently the only way to do shallow search params updates in the app router), these changes would have been overwritten by any prefetch (eg: hovering or mounting a Link), which is usually a no-op for the navigation state.
This PR changes the `sync` function to take the state as an argument rather than as a closure. The whole app router state is also unwrapped only once, and fed to the HistoryUpdater. Changes to its contents made by reducers will cause the HistoryUpdater effect to re-run, triggering history updates and a call to the sync function.
## Context
I maintain [`next-usequerystate`](https://github.com/47ng/next-usequerystate), which is used in the Vercel dashboard, and which is impacted by this change (see
[#388](https://github.com/47ng/next-usequerystate/issues/388)).
## History
@timneutkens introduced the `sync` function and the whole Redux devtools reducer in vercel/next.js#39866, with the note:
> a new hook useReducerWithReduxDevtools has been added, we'll probably want to put this behind a compile-time flag when the new router is marked stable but until then it's useful to have it enabled by default (only
when you have Redux Devtools installed ofcourse).
If a different direction is needed to keep sending `RENDER_SYNC` actions to Redux devtools, I'll be happy to rework this PR to move the `sync` function into the action queue.
## Changes
- [x] Added e2e test. Requires a `start` mode as prefetch links are disabled in development. Test was verified to fail from next@>=12.0.2-canary.7 without the fix.
Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>