Cleanup from auditing abci shims

[batconjurer]

Describe your changes

After auditing the abci++ shims, found some small cleanups.

Indicate on which release or other PRs this topic is based on

v0.33.0

Checklist before merging to draft

• I have added a changelog
• Git history is in acceptable state

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 59.40%. Comparing base (97ec5b4) to head (5200f0f).
Report is 4 commits behind head on main.

Files	Patch %	Lines
...ates/apps/src/lib/node/ledger/shims/abcipp_shim.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2861   +/-   ##
=======================================
  Coverage   59.39%   59.40%           
=======================================
  Files         298      298           
  Lines       92771    92761   -10     
=======================================
+ Hits        55104    55107    +3     
+ Misses      37667    37654   -13     

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