message: refactor(trx account lib): add constants to clarify code
  Add constants in createTransaction method to clarify code
  stlx-1601
diff: @@ -244,14 +244,13 @@ export class ContractCallBuilder extends TransactionBuilder {
  private createTransaction(): void {
  const rawDataHex = this.getRawDataHex();
  const rawData = decodeTransaction(rawDataHex);
  - (rawData
  - .contract[0] as TriggerSmartContract).parameter.value.contract_address = this._toContractAddress.toLocaleLowerCase();
  - (rawData
  - .contract[0] as TriggerSmartContract).parameter.value.owner_address = this._ownerAddress.toLocaleLowerCase();
  - (rawData.contract[0] as TriggerSmartContract).parameter.value.data = this._data.toLocaleLowerCase();
  - (rawData.contract[0] as TriggerSmartContract).parameter.type_url =
  - 'type.googleapis.com/protocol.TriggerSmartContract';
  - (rawData.contract[0] as TriggerSmartContract).type = 'TriggerSmartContract';
  + const contract = rawData.contract[0] as TriggerSmartContract;
  + const contractParameter = contract.parameter;
  + contractParameter.value.contract_address = this._toContractAddress.toLocaleLowerCase();
  + contractParameter.value.owner_address = this._ownerAddress.toLocaleLowerCase();
  + contractParameter.value.data = this._data.toLocaleLowerCase();
  + contractParameter.type_url = 'type.googleapis.com/protocol.TriggerSmartContract';
  + contract.type = 'TriggerSmartContract';
  const hexBuffer = Buffer.from(rawDataHex, 'hex');
  const id = createHash('sha256')
  .update(hexBuffer)
  