accounts-db: 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

Attention: Patch coverage is 77.50000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 83.2%. Comparing base (4807a7a) to head (3d6a4ad).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##           master    #6963     +/-   ##
=========================================
- Coverage    83.2%    83.2%   -0.1%     
=========================================
  Files         856      856             
  Lines      376390   376393      +3     
=========================================
- Hits       313281   313274      -7     
- Misses      63109    63119     +10     

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[brooksprumo]

[HaoranYi]

lgtm.