Merge Feat/proxy-tx-status in main

[popenta]

• The ApiNetworkProvider has not suffered any changes.

• The isCompleted field of the TransactionOnNetwork class is now optional.

• When using the ProxyNetworkProvider to get a transaction's status, we are using the /process-status route.

• For the proxy provider, the isCompleted field will only be set if ProxyNetworkProvider.getTransaction() is called using withProcessStatus = True.

Here's an example:

let proxy = new ProxyNetworkProvider("https://devnet-gateway.multiversx.com");
let transaction = proxy.getTransaction("txHash", True);