Simplify logic around std::optional<bool>

[vil02]

This change simplifies the assertions involving std::optional<bool>.

Continuation of #556.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.06%. Comparing base (fb8de4e) to head (4fb8619).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #557      +/-   ##
==========================================
+ Coverage   97.05%   97.06%   +0.01%     
==========================================
  Files          98       98              
  Lines       11333    11291      -42     
  Branches      796      796              
==========================================
- Hits        10999    10960      -39     
+ Misses        334      331       -3     

Flag	Coverage Δ
unittests	97.06% <100.00%> (+0.01%)	⬆️

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