Code clean-up remained from v0.37.0

[Farhad-Shabani]

Closes: #XXX

Caught my eye while reviewing different message types for adding missing checks.

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PR author checklist:

• Added changelog entry, using unclog.
• Added tests.
• Linked to GitHub issue.
• Updated code comments and documentation (e.g., docs/).
• Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01 ⚠️

Comparison is base (014fec6) 73.19% compared to head (959ad12) 73.19%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #622      +/-   ##
==========================================
- Coverage   73.19%   73.19%   -0.01%     
==========================================
  Files         125      125              
  Lines       15660    15659       -1     
==========================================
- Hits        11463    11462       -1     
  Misses       4197     4197              

Impacted Files	Coverage Δ
crates/ibc/src/clients/ics07_tendermint/error.rs	19.04% <ø> (ø)
crates/ibc/src/clients/ics07_tendermint/header.rs	84.96% <100.00%> (ø)
...ibc/src/core/ics02_client/handler/update_client.rs	100.00% <100.00%> (ø)

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