fix: Improve loan invariant message

[Tapanito]

High Level Overview of Change

Note, there are no unit-tests to update. These will come later, as part of Lending 1.1.

Changing a log message does not require an amendment.

Context of Change

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[xrplf-ai-reviewer]

No issues found. Code looks good!

Review by Claude Opus 4.6 · Prompt: V12

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.4%. Comparing base (2c765f6) to head (3de5a5a).
⚠️ Report is 46 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/libxrpl/tx/invariants/LoanInvariant.cpp	0.0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #6668   +/-   ##
=======================================
  Coverage     81.4%   81.4%           
=======================================
  Files          998     998           
  Lines        74443   74442    -1     
  Branches      7563    7558    -5     
=======================================
  Hits         60632   60632           
+ Misses       13811   13810    -1     

Files with missing lines	Coverage Δ
src/libxrpl/tx/invariants/LoanInvariant.cpp	83.2% <0.0%> (+0.7%)	⬆️

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