Fix ClientUpdateProposal for IBC v3

[alpe]

The the proposal content was changed and simplified!

// ClientUpdateProposal is a governance proposal. If it passes, the substitute
// client's latest consensus state is copied over to the subject client. The proposal
// handler may fail if the subject and the substitute do not match in client and
// chain parameters (with exception to latest height, frozen height, and chain-id).

ClientUpdateProposal https://github.com/cosmos/ibc-go/blob/main/proto/ibc/core/client/v1/client.proto#L43

[daniellarita]

thanks for taking this one @hashedone ! let us know if you run into any blockers

[hashedone]

@daniellarita unfortunately more I am reading the code around, the less I am positive I have an idea of what to do. The gov proposals in tgrade are handled in https://github.com/confio/tgrade/blob/v1.0.1/x/twasm/contract/incoming_msgs.go#L61. There is no handler for ClientUpdate, but there is the IBCClientUpdate proposal. I could assume it is the same, considering the IBCClientUpdate seems to match what is in the ClientUpdate, the problem is - if it matches should it be changed right now? Shouldn't it be first properly handled on the binary side? Or maybe there should be a new message ClientUpdate which will be added to tgrade?

For now, my best bet is - ClientUpdate should be changed to IBCClientUpdate and its structure should be aligned. I can do that. I will prepare PR for that, but if something should be understood differently please give me some lead.

[daniellarita]

Thanks for the update! @alpe @pinosu can you provide @hashedone with some clarification/ feedback on if his approach makes sense? Thanks!

[alpe]

The ClientUpdateProposal is a new proposal type that does not exists in tgrade yet. When implemented in the contract side, the integration in tgrade can start the contract object back to the proper ibc content type