Fix asset transfer test

[salman01zp]

Summary of changes

• If we use transact method from Vanchor class here It pads inputs(2/16) and output(2) with dummy utxos before calling contracts method.

In relayer, we directly call contract and thus need to pad inputs(2/16) and output(2) with dummy utxos in test to fix asset transfer test.

Reference issue to close (if applicable)

• Closes #373

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Code Checklist

• [ ] Tested
• [ ] Documented