exporters3d.py -> add "build123d" to exported step files, change step "Name" to build123d label

[jdegenstein]

This appears to work in OCP 7.8+ now.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.61%. Comparing base (d78ca93) to head (9ce9306).
Report is 9 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #876      +/-   ##
==========================================
+ Coverage   96.58%   96.61%   +0.03%     
==========================================
  Files          31       31              
  Lines        9124     9139      +15     
==========================================
+ Hits         8812     8830      +18     
+ Misses        312      309       -3     

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[jdegenstein]

Changes STEP file header from:

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('Open CASCADE Model'),'2;1');
FILE_NAME('Open CASCADE Shape Model','2025-01-18T15:53:37',('Author'),('Open CASCADE'),
  'Open CASCADE STEP processor 7.8','Open CASCADE 7.8','Unknown');
...

To:

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('Open CASCADE Model'),'2;1');
FILE_NAME('Open CASCADE Shape Model','2025-01-18T15:54:27',('Author'),(
    'Open CASCADE'),'Open CASCADE STEP processor 7.8','build123d',
  'Unknown');
...