FIX: Contract class difference error

[megabyte0x]

Description

As per the current tutorial, the deployment of the token contract is being done with the Contract class while the instance of it for getToken function is created using the TokenContract class, and upon executing the script to fetch balance it's throwing the following error:

Error while retrying JsonRpcClient request pxe_updateContract to http://localhost:8080: Error: Error 500 from server http://localhost:8080 on pxe_updateContract: Could not update contract to a class different from the current one.
    at <anonymous> (/Users/sample_dapp/node_modules/@aztec/foundation/dest/json-rpc/client/fetch.js:59:23)
    at processTicksAndRejections (:12:39) {
  originalLine: 43,
  originalColumn: 22
}

Fix

Keep the Contract class constant for both the deployment and instance creation for the tutorial.

[critesjosh]

closing as duplicate #12802