Layout component remounts when throwing an error in an action

[brookslybrand]

Reproduction

https://stackblitz.com/edit/remix-run-remix-h3kxyf?file=app%2Froot.tsx,app%2Froutes%2F_index.tsx

System Info

System:
    OS: macOS 14.6.1
    CPU: (8) arm64 Apple M1 Pro
    Memory: 285.50 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.17.0 - ~/.nvm/versions/node/v20.17.0/bin/node
    npm: 10.8.3 - ~/.nvm/versions/node/v20.17.0/bin/npm
    pnpm: 9.10.0 - ~/Library/pnpm/pnpm
    bun: 1.1.0 - ~/.bun/bin/bun
  Browsers:
    Chrome: 128.0.6613.138
    Safari: 17.6
  npmPackages:
    vite: 5.4.0 => 5.4.0 

### Used Package Manager

npm

### Expected Behavior

According to the [Layout docs](Avoids React from re-mounting your app shell elements when switching between the root component/HydrateFallback/ErrorBoundary which can cause a FOUC if React removes and re-adds <link rel="stylesheet"> tags from your <Links> component.)

> Avoids React from re-mounting your app shell elements when switching between the root component/HydrateFallback/ErrorBoundary which can cause a FOUC if React removes and re-adds <link rel="stylesheet"> tags from your <Links> component.

### Actual Behavior

It looks like the `Layout` component in `root.tsx` is remounting if you throw an error from an `action`. If you put an `ErrorBoundary` inside of the child (`routes/_index.tsx`) the remounting goes away and works the way I would expect.

Either:
1. This is a bug
2. This is intended for some reason, and we need to clarify the language in the documentation


https://github.com/user-attachments/assets/86339e99-953b-46f1-ab1c-549920e6f2b2