Retire fix1571 Amendment

[pratikmankawde]

High Level Overview of Change

This change retires the fix1571 amendment.

Context of Change

Original amendment: https://xrpl.org/resources/known-amendments#fix1571
Amendments activated for more than 2 years can be retired.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Performance (increase or change in throughput and/or latency)
• Tests (you added tests for code that already exists, or your new feature included in this PR)
• Documentation update
• Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
• Release

[pratikmankawde]

@ximinez Can you please confirm if this new unit test which checks presence of cancel time and finish time combination is correct?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.5%. Comparing base (e192ffe) to head (06e0766).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5925   +/-   ##
=======================================
  Coverage     78.5%   78.5%           
=======================================
  Files          817     817           
  Lines        69017   69013    -4     
  Branches      8276    8275    -1     
=======================================
- Hits         54197   54196    -1     
+ Misses       14820   14817    -3     

Files with missing lines	Coverage Δ
src/xrpld/app/tx/detail/Escrow.cpp	99.2% <100.0%> (-<0.1%)	⬇️

... and 1 file with indirect coverage changes

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