[BUG] Drop outbound tx that fail to broadcast to binance due to memo flag

Binance can set memo flag on address, if an address has memo flag set, then thorchain won't be able to send fund to it

{
    "jsonrpc": "2.0",
    "id": "",
    "result": {
        "check_tx": {
            "code": 65552,
            "log": "{\"codespace\":1,\"code\":16,\"abci_code\":65552,\"message\":\"The receiver requires the memo contains only digits.\"}",
            "events": [
                {
                    "attributes": [
                        {
                            "key": "YWN0aW9u",
                            "value": "c2VuZA=="
                        }
                    ]
                }
            ]
        },
        "deliver_tx": {},
        "hash": "7047ED63FC01ED675DEE225A0CF5B010937CB8716DF7DFE97A784CC026D829AF",
        "height": "0"
    }
}