Add motif thresholding figure

[katiekly]

• Solves Add motif thresholding #45

[codecov]

Codecov Report

Attention: Patch coverage is 34.78261% with 15 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/vame/analysis/pose_segmentation.py	34.78%	15 Missing ⚠️

Files with missing lines	Coverage Δ
src/vame/analysis/pose_segmentation.py	75.86% <34.78%> (-4.25%)	⬇️

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