fix: update human-in-the-loop tutorial with better system message to signal termination condition

[ekzhu]

Resolves #5248

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.40%. Comparing base (2f1684b) to head (3d8f305).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5253   +/-   ##
=======================================
  Coverage   70.40%   70.40%           
=======================================
  Files         179      179           
  Lines       11615    11615           
=======================================
  Hits         8177     8177           
  Misses       3438     3438           

Flag	Coverage Δ
unittests	70.40% <ø> (ø)

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