Validate and refactor ICS20 sendPacket flow

[srdtrk]

Summary

While implementing 3-chain workflows, several bugs were discovered in ICS20 sendPacket flow (both in solidity-ibc-eureka and ibc-go). The goal of this issue is to validate/refactor the design of sendPacket flow in solidity-ibc-eureka and implement new tests for this flow.

Problem Definition

While implementing #215, I ran into the following bugs:

• Originator chain is source but packet denom is not contract address #216
• Users can directly transfer hashed IBC denoms using MsgSendPacket ibc-go#7848

Both of which could be the signs of a larger design flaw. At this moment, it is not clear whether or not cosmos/ibc-go#7848 affects solidity-ibc-eureka.

Next Steps

• Have an internal discussion on Originator chain is source but packet denom is not contract address #216 and Users can directly transfer hashed IBC denoms using MsgSendPacket ibc-go#7848 and determine if sendPacket flow needs to be refactored in this repo.
• Determine requirements for sufficient testing. These tests should at least show that the two bugs mentioned no longer affect this repository.
• Make a single PR refactoring sendPacket flow (if needed) which also includes all the necessary tests

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned
• Estimate provided

[srdtrk]

We've decided to refactor the sendPacket flow not to directly use payload and instead use MsgTransfer