Remove unsignedTx from the generated deployment file

[polarker]

It's a bit heavy and not necessary since tx id is stored

[Lbqds]

When the user calls deployer.deployContract, they might want to check the unsignedTx. So there is an unsignedTx field in the DeployContractResult. We store the unsignedTx in the deployment file because if the contract has already been deployed, we can directly return the result from here.

However, it's still possible to remove unsignedTx from the deployment file. We can get tx info from the full node using the tx id, but we cannot directly get the encoded unsigned tx. We can use tx-codec to encode it into a hex string. WDYT?