Omitting port in server URI sets port to 0
If I create a `MoneroWalletFull` with server URI without port like `https://monerod.slvit.us`, the fetch requests are going to be look like `https://monerod.slvit.us:0/json_rpc` and fail.

To work around this I need to set server to `https://monerod.slvit.us:443` which is unnecessary verboe