Migrate 02-client to use proto encoded/decoded client states

[colin-axner]

Description

Followup to #6932

Migrates client states to use codec.BinaryMarshaler in 02-client. ClientState will now be passed around as a pointer. We need to maintain the amino codec registration until the flip is switched on amino encoding genesis, which will occur once IBC genesis is migrated (after consensus states migration).

Consensus state migration should be able to occur after we change the validator set to be a hash in the tendermint client: #6942. I'll probably do this change in 2 steps like client state, migrate tendermint consensus state, then flip the switch in 02-client

ref: #6254

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[codecov]

Codecov Report

Merging #6948 into master will increase coverage by 0.01%.
The diff coverage is 72.54%.

@@            Coverage Diff             @@
##           master    #6948      +/-   ##
==========================================
+ Coverage   61.78%   61.80%   +0.01%     
==========================================
  Files         520      521       +1     
  Lines       32147    32163      +16     
==========================================
+ Hits        19861    19877      +16     
+ Misses      10676    10672       -4     
- Partials     1610     1614       +4     

[colin-axner]

we don't need this because 09-localhost does not internal amino encoding, just registration is needed to decode/encode client states at genesis and exporting genesis

[fedekunze]

utACK

[colin-axner]

@fedekunze test-sim-after-import and test-sim-import-export failed, but I can't tell why. Should we revert? I expect it'd be fixed after full migration, but I don't know how long until full migration is done. Maybe it is just a genesis issue?

[colin-axner]

we identified the fix, non-empty genesis states weren't being tested in regular tests. I forgot to update the genesis client states to be pointers. Will post a fix with tests (probably won't get it done until tomorrow