refactor(plugin-htlc-eth-besu): stop using the deprecated api.encodePacked

[petermetz]

Description

Stop using the abi.encodePacked() call in the packages/cactus-plugin-htlc-eth-besu/src/main/solidity/contracts/HashTimeLock.sol contract because that method has been deprecated according to [1]

[1] ethereum/solidity#11593

Acceptance Criteria

1. Tests are still passing
2. The new encoding call does not make this a breaking change, e.g. the outputs are consistent so that the test cases do not need to be changed to keep passing after the contract have been re-deployed.
3. Make sure to update the compiled .json artifact of the .sol source code file so that the tests do end up using the new revision of the .sol code.

cc: @RafaelAPB

[RafaelAPB]

I'll do this task

[RafaelAPB]

Done, PR #2538