Preserve non-UTF-8 bytes in simulator dialogues

[aamir-azeez]

Fixes #227, reported by BT8298.

Dialogue bytes that are not UTF-8 can raise UnicodeDecodeError. Preserve those bytes during dialogue matching and response formatting; skip text-only setters only if UTF-8 decoding fails.

The suite passes.

[codecov]

Codecov Report

❌ Patch coverage is 97.14286% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.92%. Comparing base (55a5ce3) to head (ceeb722).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...a_sim/testsuite/test_binary_dialogue_regression.py	96.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #241      +/-   ##
==========================================
+ Coverage   86.78%   87.92%   +1.13%     
==========================================
  Files          19       20       +1     
  Lines        1052     1118      +66     
  Branches      114      116       +2     
==========================================
+ Hits          913      983      +70     
+ Misses        104      103       -1     
+ Partials       35       32       -3     

Flag	Coverage Δ
unittests	87.92% <97.14%> (+1.13%)	⬆️

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