fix: Use the correct unit registry in pint

[nsmith-]

As it turns out, using pint.Quantity(val, unit) uses a different registry than val * unit when we want to use the registry of unit

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.71%. Comparing base (1b2cdee) to head (62883e9).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #275      +/-   ##
==========================================
+ Coverage   98.67%   98.71%   +0.04%     
==========================================
  Files           7        7              
  Lines         301      311      +10     
==========================================
+ Hits          297      307      +10     
  Misses          4        4              

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[eduardo-rodrigues]

Thanks for this.