validator: Resolve Rust 1.88 clippy lints and format strings

[steviez]

Problem

Working towards #6850, broken out from #6854

Summary of Changes

• Run cargo clippy --fix --tests with Rust 1.88.0 set in rust-toolchain.toml
  • These should only be instances of uninlined_format_args
• Run cargo fmt with format_strings = true set in rustfmt.toml

[codecov-commenter]

Codecov Report

❌ Patch coverage is 75.10373% with 60 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.4%. Comparing base (61cc874) to head (b675f43).
⚠️ Report is 14 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7582   +/-   ##
=======================================
  Coverage    83.4%    83.4%           
=======================================
  Files         813      813           
  Lines      365104   365089   -15     
=======================================
+ Hits       304530   304568   +38     
+ Misses      60574    60521   -53     

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[brooksprumo]