Fix ABI buffer encoding

[janniks]

I remember we've discussed this before, but I can't find or remember the answer. When calling a function, the explorer processes buff argument inputs as ascii instead of as hex. Is there any way to make it process the input as hex bytes?

Actually I think the problem is in stacks.js

stacks.js/packages/transactions/src/contract-abi.ts

Lines 174 to 175 in f39637c

	case ClarityAbiTypeId.ClarityAbiTypeBuffer:
	return bufferCV(utf8ToBytes(val));

(https://github.com/hirosystems/stacks.js/blob/f39637c924cc8b221f890a8bd9f8e0c9fb1f90e6/packages/transactions/src/contract-abi.ts)
case ClarityAbiTypeId.ClarityAbiTypeBuffer:
return bufferCV(utf8ToBytes(val));