Broadcaster fails on submitting transaction when the bech32 prefix of the chain is different with sdk.Config

[madrezaz]

This issue is similar to #898; the TX broadcaster contains the following code:

account, err := clientContext.AccountRetriever.GetAccount(clientContext, sdkAdd)

which is failed since the AccountRetriever is the auth module's implementation and uses the following function:

res, err := queryClient.Account(context.Background(), &QueryAccountRequest{Address: addr.String()}, grpc.Header(&header))

where addr.String() uses the static bech32 prefix and leads to the failure of this query when the chain's prefix is different.