message: fix(core): hard code zcash transaction version
  This is not ideal, but the ZCASH_SAPLING_VERSION is missing from the
  latest version of utxo lib, so zcash sends are not working currently.
  Ticket:
diff: @@ -49,7 +49,8 @@ export class Zec extends AbstractUtxoCoin {
  * @returns {*}
  */
  prepareTransactionBuilder(txBuilder: ZecTransactionBuilder): any {
  - txBuilder.setVersion(bitGoUtxoLib.Transaction.ZCASH_SAPLING_VERSION);
  + // sapling transaction version, see modules/utxo-lib/src/forks/zcash/version
  + txBuilder.setVersion(4);
  txBuilder.setVersionGroupId(0x892f2085);
  // Use "Canopy" consensus branch https://zips.z.cash/zip-0251
  // https://bitgoinc.atlassian.net/browse/BG-26072
  