Don't send a client update if consensus state already exists

[ancazamfir]

Summary

With the fix for #2087, because multiple batches perform client update at same height we see the following warnings:

2022-05-13T11:09:32.471130Z  WARN ThreadId(290) packet_cmd{src_chain=ibc-0 src_port=transfer src_channel=channel-1 dst_chain=ibc-1}:clear:schedule_recv_packet_and_timeout_msgs{h=Some(Height { revision: 0, height: 599 })}:schedule{odata=oHMVz0CGiB ->Destination @0-599; len=50}: [ibc-0 -> ibc-1:07-tendermint-1] resolving trusted height from the full list of consensus state heights for target height 0-600; this may take a while

Then things proceed and work is wasted for an updated that it is not needed.

Problem Definition

Proposal

Add a check in update client for client_latest_height == target_height and make it a noop in this case.

Acceptance Criteria

The warning above is not seen and the client update is not issued if the chain already has the consensus state.

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[romac]

Done in #3555