default request args

[zeroXbrock]

• adds customRpc to getSuaveWallet args, which allows the wallet to access an alternate RPC (i.e. not the RPC to which the wallet is currently connected) when signing & sending txs (getting nonce, gas price)
• this fixes common nonce & gas errors arising from custom-transport (browser) wallets being connected to an RPC other than suave

example usage in a web app:

const suaveWallet = getSuaveWallet({
    jsonRpcAccount: "0xBE69d72ca5f88aCba033a063dF5DBe43a4148De0",
    transport: custom(window.ethereum),
    customRpc: "http://localhost:8545",
})

const ccr: TransactionRequestSuave = {
    to: "0xd594760b2a36467ec7f0267382564772d7b0b73c",
    data: getCalldata(), // pretend you have this
    isEIP712: true, // true is default; can be omitted
    kettleAddress: "0xb5feafbdd752ad52afb7e1bd2e40432a485bbb7f",
    confidentialInputs: getConfidentialInputsBytes(), // pretend you have this
}

await suaveWallet.sendTransaction(ccr)

If you don't specify customRpc, the wallet will fall back on the provided custom transport, which will cause errors if the user's wallet is not connected to the suave RPC (which was the behavior prior to this PR).