Updates with-supertokens example: Fixes init race condition (#32706)

Updates with-supertokens example to fix a race condition for initialising the supertokens-node SDK. Earlier we used to do it in _app.js in an async manner, so if `getServerSideProps` is called before the `supertokens.init` is called, the page load would fail. 

Now, we call `supertokens.init` (for the node SDK) in the `getServerSideProps` function itself.

Co-authored-by: kant01ne <5072452+kant01ne@users.noreply.github.com>
Co-authored-by: Bhumil Sarvaiya <21988812+bhumilsarvaiya@users.noreply.github.com>
Co-authored-by: Joel Coutinho <6310783+jscyo@users.noreply.github.com>

examples/with-supertokens/pages/_app.js

@@ -6,16 +6,8 @@ import * as SuperTokensConfig from '../config/frontendConfig'
 import Session from 'supertokens-auth-react/recipe/session'
 import { redirectToAuth } from 'supertokens-auth-react/recipe/thirdpartyemailpassword'
 
-async function initNode() {
-  const supertokensNode = await import('supertokens-node')
-  const { backendConfig } = await import('../config/backendConfig')
-  supertokensNode.init(backendConfig())
-}
-
 if (typeof window !== 'undefined') {
   SuperTokensReact.init(SuperTokensConfig.frontendConfig())
-} else {
-  initNode().catch(console.error)
 }
 
 function MyApp({ Component, pageProps }) {

examples/with-supertokens/pages/index.js

@@ -3,6 +3,8 @@ import Head from 'next/head'
 import styles from '../styles/Home.module.css'
 import ThirdPartyEmailPassword from 'supertokens-auth-react/recipe/thirdpartyemailpassword'
 import dynamic from 'next/dynamic'
+import supertokensNode from 'supertokens-node'
+import { backendConfig } from '../config/backendConfig'
 import Session from 'supertokens-node/recipe/session'
 
 const ThirdPartyEmailPasswordAuthNoSSR = dynamic(
@@ -13,6 +15,8 @@ const ThirdPartyEmailPasswordAuthNoSSR = dynamic(
 )
 
 export async function getServerSideProps(context) {
+  // this runs on the backend, so we must call init on supertokens-node SDK
+  supertokensNode.init(backendConfig())
   let session
   try {
     session = await Session.getSession(context.req, context.res)