docs: remove unused viemAdaptor import example

Author: coreyar

apps/portal/src/app/react/v5/adapters/page.mdx

@@ -94,7 +94,6 @@ import { defineChain } from 'thirdweb'
 import { useSetActiveWallet } from 'thirdweb/react'
 import { createWalletAdapter } from 'thirdweb/wallets'
 import { useDisconnect, useSwitchChain, useWalletClient } from 'wagmi'
-import { viemAdapter } from "thirdweb/adapters/viem";
 import { client } from './client'