Incomplete ICS 007 ClientState verification methods implementation

[adizere]

Crate

ibc

Summary

Incomplete implementation of check_header_and_update_state

• We should add a check that incoming header's trusted_validators matches the next_validators_hash that was persisted in the trusted consensus state
  • Equivalent check in ibc-go is here: https://github.com/cosmos/ibc-go/blob/147e0f1954ede691bb977ff185b9d0500ec4bd0a/modules/light-clients/07-tendermint/types/update.go#L152
  • The check is significant b/c the header's trusted_validator_set is used in the trusted block state in verify:

    ibc-rs/modules/src/clients/ics07_tendermint/client_def.rs

    Line 98 in b44ade9

    next_validators: &header.trusted_validator_set,

We should fix (or investigate) the following remarks regarding verification of ICS007 ClientState.

• Unrelated to this issue, but I see that ibc-go restricts 07-tendermint ChainIds to tendermint::MaxChainID -> TM chain-id validation cosmos/ibc-go#177

Originally posted by @hu55a1n1 in https://github.com/informalsystems/ibc-rs/pull/1873#discussion_r809993503

• We're also not checking if the latest_height's revision_number matches the ChainId's version.

Originally posted by @hu55a1n1 in https://github.com/informalsystems/ibc-rs/pull/1873#discussion_r810002577

• ibc-go doesn't allow a zero max_clock_drift. Not sure why this would be required. 🤔

Originally posted by @hu55a1n1 in https://github.com/informalsystems/ibc-rs/pull/1873#discussion_r810004141

• Apparently, each key in upgrade_path must be non-empty and this must also be checked.

Originally posted by @hu55a1n1 in https://github.com/informalsystems/ibc-rs/pull/1873#discussion_r810018385

Acceptance Criteria

• Implement the verification checks mentioned above.
• Add tests similar these -> https://github.com/cosmos/ibc-go/blob/main/modules/light-clients/07-tendermint/types/client_state_test.go#L95

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