Add API-less, UTXO-based ordinal detection heuristic

[sneurlax]

obviate the API call, try detection via "2nd witness commitment": https://bitcoin.stackexchange.com/questions/118567/how-can-we-check-if-a-transaction-is-an-ordinal-transaction-in-the-mempool

[sneurlax]

ie replace the <10000sats check from https://github.com/cypherstack/stack_wallet/blob/staging/lib/services/coins/litecoin/litecoin_wallet.dart#L1899-L1904 with something like the above

[sneurlax]

and replace the API call above that linked snippet w the same

[sneurlax]

Look for ASCII "ord" (hex 6f7264) in the [second to last] output

[sneurlax]

Closed but not completed.