ENH: cut streamlines min length

[AntoineTheb]

Quick description

Change the minimum length of streamlines output by scil_tractogram_cut_streamlines to 0, as the previous behavior was confusing.

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Type of change

Check the relevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the style guidelines of this project (run autopep8)
• I added relevant citations to scripts, modules and functions docstrings and descriptions
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• X ] My changes generate no new warnings
• I moved all functions from the script file (except the argparser and main) to scilpy modules
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.79%. Comparing base (92a2010) to head (d4ba290).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1040   +/-   ##
=======================================
  Coverage   68.79%   68.79%           
=======================================
  Files         432      432           
  Lines       22456    22456           
  Branches     3038     3038           
=======================================
  Hits        15449    15449           
  Misses       5709     5709           
  Partials     1298     1298           

Components	Coverage Δ
Scripts	69.66% <100.00%> (ø)
Library	67.56% <ø> (ø)