[WAVE 1] Test printing OCPs without controls

[mickaelbegon]

Summary

• add a focused regression test for ocp.print() with no control variables
• cover both console output and Graphviz graph preparation
• update the dormant ControlType.NONE fixture to the current dynamics signature
• make the fixture honor its n_phase argument so the regression stays lightweight

Context

The production printing code now skips empty control collections correctly, so the historical crash is no longer reproducible. However, the existing no-control test returned before constructing its OCP and could not protect this behavior. This PR restores a small executable path specifically for the reported issue.

Validation

• MPLCONFIGDIR=/private/tmp/bioptim-mpl-637 python -m pytest tests/shard6/test_controltype_none.py::test_print_control_type_none -q (1 passed)
• git diff --check

Closes #637

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This change is 

[mickaelbegon]

Wave 1 preparation update: this PR does not touch plotting code. Its shared Matplotlib failure is addressed by prerequisite #1081; it will remain draft until that prerequisite lands and CI is rerun.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.26%. Comparing base (5ed90c1) to head (fcd3159).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1069   +/-   ##
=======================================
  Coverage   77.26%   77.26%           
=======================================
  Files         196      196           
  Lines       21506    21506           
=======================================
  Hits        16616    16616           
  Misses       4890     4890           

Flag	Coverage Δ
unittests	77.26% <ø> (ø)

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