mnemonicToPrivateKey method
Implementation
@override
Future<Uint8List> mnemonicToPrivateKey(String mnemonic) async {
// Taproot always derives on the BIP86 path, independent of the network
// carried by [setting]; other script types honour the setting's path.
final path = isTaproot ? TAPROOT_PATH : setting!.bip44Path;
return HDWallet.bip32DerivePath(mnemonic, path);
}