Add needed unit or integration tests for Tendermint proof verifications

[Farhad-Shabani]

Summary

There is a need to cover Tendermint proof verifications with proper tests after issue #396.
Mock Chain passes the proof verifications and we are not able to catch Tendermint-specific errors with the existing tests.

To Do

To ensure Tendermint proof verifications are correctly executed, we should add corresponding unit tests or somehow integrate basecoin-rs into our CI process

Blocked on: #677

[plafer]

#396 was a core IBC bug; not Tendermint-specific. Did you mean "core handler validation needs to be tested" instead of "Tendermint proof verifications"?

[Farhad-Shabani]

It occurred in the core section, but catching such errors needs that tests go through a proof verification process (e.g. here), which is a client-specific action. So, we can match the output with the fed test data.
Note that we already bypass this check for MockClientState by setting the result of such methods to Ok() (e.g. here)

[plafer]

Ah I see; yes that's right.

[rnbguy]

closed by #1109