[ICS07] Client/ConsensusState bytes for upgrade_client validation should be derived from prost

[Farhad-Shabani]

Bug Summary

verify_upgrade_client method encodes (e.g. here) upgraded_client/cons_state incorrectly.

Proposal

We should instead use prost::Message:

        let mut client_state_value = Vec::new();
        upgraded_client_state
            .encode(&mut client_state_value)
            .map_err(ClientError::Encode)?;

Version

v0.40.0