Add multi-chain IBC v2 E2E testing package and test cases

[vladjdk]

Problem

Add test coverage to ensure that IBC-related logic works correctly across both v1 and v2 after bump up ibc-go version from v8 to v10.

Closing criteria

Add e2e test coverage for both IBC v1 and IBC v2 functionality using ExampleChain.

Problem details

Previously, there was no dedicated test coverage verifying whether IBC functionality (send/receive logic, relaying, etc.) worked correctly.
This issue aims to add in-memory e2e tests that spin up ExampleChain instances and simulate IBC packet flow between them.

Although we refer to these as e2e tests, note that:

• They are not dockerized container-based tests.
• Instead, we use in-memory chain instances with a mocked relayer to verify that messages are properly sent and processed between app chains.

Additional note:

• Native ERC20 coins cannot currently be tested on the IBC v2 router because their denoms have the erc20/ prefix, and IBC v2 does not allow sending tokens with base denoms that include /. This limitation may be resolved once this issue is addressed.