deprecated mumbai, updated to amoy

[Tgemayel]

This repository using the Mumbai testnet which was deprecated since 08/04/2024.

Updated Chain Configuration:

export const chainConst = {
  chainId: 80002,
  rpc: ["https://80002.rpc.thirdweb.com"],
  nativeCurrency: {
    name: "MATIC",
    symbol: "MATIC",
    decimals: 18,
  },
  chain: "Polygon",
  shortName: "amoy",
  name: "Polygon Amoy Testnet",
  testnet: true,
};