Update Redux example to use Toolkit + update dependencies. (vercel#29104)

After talking with markerikson, I've made some updates to the Redux examples:

- Updated the `with-redux` example to use the Redux Toolkit + TypeScript example
- Updated dependencies of `with-redux` to work with latest testing setup
- Removed `with-redux-toolkit` in favor of `with-redux`
- Removed `with-redux-toolkit-typescript` in favor of `with-redux`
- Removed `with-redux-code-splitting` in favor of `with-redux`

Author: leerob

examples/with-redux-code-splitting/.gitignore

@@ -1,23 +1 @@
-# Redux Toolkit TypeScript Example
-
-This example shows how to integrate Next.js with [Redux Toolkit](https://redux-toolkit.js.org).
-
-The **Redux Toolkit** is a standardized way to write Redux logic (create actions and reducers, setup the store with some default middlewares like redux devtools extension). This example demonstrates each of these features with Next.js
-
-## Deploy your own
-
-Deploy the example using [Vercel](https://vercel.com?utm_source=github&utm_medium=readme&utm_campaign=next-example):
-
-[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/git/external?repository-url=https://github.com/vercel/next.js/tree/canary/examples/with-redux-toolkit-typescript&project-name=with-redux-toolkit&repository-name=with-redux-toolkit)
-
-## How to use
-
-Execute [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app) with [npm](https://docs.npmjs.com/cli/init) or [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/) to bootstrap the example:
-
-```bash
-npx create-next-app --example with-redux-toolkit-typescript with-redux-toolkit-app
-# or
-yarn create next-app --example with-redux-toolkit-typescript with-redux-toolkit-app
-```
-
-Deploy it to the cloud with [Vercel](https://vercel.com/new?utm_source=github&utm_medium=readme&utm_campaign=next-example) ([Documentation](https://nextjs.org/docs/deployment)).
+This example has been moved to [with-redux](https://github.com/vercel/next.js/tree/canary/examples/with-redux).