hotfix: show xrp balance when hitting clio (#834)

Clio moved the `signer_list` property for `account_info`. This is a
temporary fix and does not fix showing signer lists on an accounts page
but the balance is more important.

src/rippled/accountState.js

@@ -106,7 +106,7 @@ const getAccountState = (account, rippledSocket) => {
         info: formatAccountInfo(info, data[3].info.validated_ledger),
         balances: data[0].balances,
         tokens: data[0].tokens,
-        signerList: info.signer_lists[0]
+        signerList: info.signer_lists?.[0]
           ? formatSignerList(info.signer_lists[0])
           : undefined,
         escrows: data[1],