tests: add ibc test cases

[zsystm]

Description

This PR adds test coverage to verify that both IBC v1 and IBC v2 flows are working as expected in ExampleChain.

Coverage

File Name	Coverage
github.com/cosmos/evm/ibc/module.go	100.0%
github.com/cosmos/evm/ibc/utils.go	100.0%
github.com/cosmos/evm/tests/ibc/helper.go	81.0%
github.com/cosmos/evm/testutil/ibc.go	100.0%
github.com/cosmos/evm/x/erc20/ibc_middleware.go	91.7%
github.com/cosmos/evm/x/erc20/keeper/ibc_callbacks.go	87.9%
github.com/cosmos/evm/x/ibc/transfer/ibc_module.go	100.0%
github.com/cosmos/evm/x/ibc/transfer/keeper/keeper.go	100.0%
github.com/cosmos/evm/x/ibc/transfer/keeper/msg_server.go	100.0%
github.com/cosmos/evm/x/ibc/transfer/module.go	72.7%
github.com/cosmos/evm/x/ibc/transfer/v2/ibc_module.go	100.0%

# How to get coverage
go test -coverpkg=./... -coverprofile=coverage.out -tags=test ./... 
go tool cover -html=coverage.out -o coverage.html

Closes: #46

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[dongsam]

Overall, this looks good to me

1. How about adding a test case to reach coverage this part as well?
2. We also need to add test cases for the ICS20-related precompile, but since the removal of authz dependency is currently in progress, it seems more efficient to handle it after that change is completed.