ICS02 keeper tests

[fedekunze]

Keeper and Querier tests are missing on ICS02. I'd leave out the tests of VerifyMembership and VerifyNonMembership as we need to update those functions in following PR to the latest IBC-RC (see cosmos/ibc#293 for reference).

cc: @AdityaSripal

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[AdityaSripal]

The keeper doesn't seem to do anything non-trivial apart from VerifyMembership, VerifyNonMembership, and CheckMisbehavior all of which is still a work in progress from my understanding.

I think the Keeper tests are blocked on getting the above done, but definitely point out anything else that should be tested in keeper

Can still test Get/Set methods

[AdityaSripal]

Closed via #5329