fix(ts): relax AppProps to not require generic (#41264)

It seems that #38867 made `AppProps` always require the `pageProps`
object shape to be passed as a generic since the default `{}` will throw
a TS error if you try accessing any property:

Before:

![image](https://user-images.githubusercontent.com/18369201/194639573-aa8a97f8-2c6a-413c-96f2-5e99e4a17c66.png)

After:

![image](https://user-images.githubusercontent.com/18369201/194639630-03d1a669-722f-4822-b0db-3b8dd88b2959.png)


Technically, it would be more correct since accessing `pageProps`
properties would otherwise be unsafe, but this seems to break the
current behavior.

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

packages/next/pages/_app.tsx

@@ -17,7 +17,7 @@ export { NextWebVitalsMetric }
 
 export type AppContext = AppContextType<Router>
 
-export type AppProps<P = {}> = AppPropsType<Router, P>
+export type AppProps<P = any> = AppPropsType<Router, P>
 
 /**
  * `App` component is used for initialize of pages. It allows for overwriting and full control of the `page` initialization.
@@ -31,7 +31,7 @@ async function appGetInitialProps({
   return { pageProps }
 }
 
-export default class App<P = {}, CP = {}, S = {}> extends React.Component<
+export default class App<P = any, CP = {}, S = {}> extends React.Component<
   P & AppProps<CP>,
   S
 > {