Add testnet evm config to viem

[bthaile]

Add the following config to viem, need to verify the properties.

https://github.com/wevm/viem/tree/main/src/chains/definitions

import { defineChain } from '../../utils/chain/defineChain.js'

export const flowTestnet = /*#__PURE__*/ defineChain({
  id: 545,
  name: 'FlowEVM Testnet',
  nativeCurrency: {
    decimals: 18,
    name: 'Flow',
    symbol: 'FLOW',
  },
  rpcUrls: {
    default: {
      http: ['https://testnet.evm.nodes.onflow.org'],
    },
  },
  blockExplorers: {
    default: {
      name: 'Testnet Explorer',
      url: 'https://testnet.flowdiver.io',
    },
  },
})

[bthaile]

Added PR to add evm testnet https://github.com/wevm/viem/pull/2144