proxyd: support `eth_sendRawTransactionSync`

[tynes]

See discussion here, but the tldr is that this cuts the number of networking roundtrips down when submitting a transaction, decreasing the latency of tx confirmation in particular for chains that have fast blocktimes.

It has been merged into geth in https://github.com/ethereum/go-ethereum/pull/32830. There is viem support for this method, would be good to have strong support in OP Stack and have applications start migrating to it to decrease latency