fix wallet init in chrome 8

context/polkadotExtensionContext.tsx

@@ -33,7 +33,7 @@ export const PolkadotExtensionProvider = ( { children } : { children : ReactNode
       // enable the wallet
       try {
         await firstWallet?.enable( "Polkadot Tokengated Demo" )
-        await firstWallet.subscribeAccounts((allAccounts: WalletAccount[] | undefined) => {
+        await firstWallet?.subscribeAccounts((allAccounts: WalletAccount[] | undefined) => {
             console.log("got accounts via talisman connect", allAccounts)
             if ( accounts === undefined || accounts.length === 0 ) {
               setAccounts( allAccounts )