`fundchannel` grpc returns txid in little-endian

### Example

A `fundchannel` call outputs this transaction (in hex here) in the `tx` field: `020000000001014e781147f985587bc671a07dbec7b5d2c76114736a8becaa461f037fa6092afa0000000000fdffffff020008af2f000000002200206c3709b130ebc072b9325fc4cc7a60406de8c07097a344da7e3abd8d477026cb5ac1eb0b0000000022512067a771c98df0f123971aef2ffd0e219e63c67157795493d323b6c018b537b6fc02473044022024807f43eb357a346858de5d013899df657c164344e0cc7ce2fac9e82f5d17b402200adfe04060886bbe0a0912cc8dfa457e49b68853a4673daa813994bc9a5900ec0121038573599ded6d7942c44565136281670bd1df817dbe94d020dd05e3cbed2dcbaa6e000000`

But the bytes in the `txid` field decode to `3e876d8ccb8d8f873a59ed379e2faf999af8b29427104366870b1214a50faca9` instead of the expected `a9ac0fa514120b876643102794b2f89a99af2f9e37ed593a878f8dcb8c6d873e`

This seems to be caused by the txid bytes being ordered in little-endian instead of big-endian