clockwise arc format is incorrectly negated

[pzpzpzp2]

https://github.com/PrincetonLIPS/SketchGraphs/blob/1f27f5f9459926d38318007c71b72697083b2f3c/sketchgraphs/data/_plotting.py#L46C9-L46C54

Looking at this line of code for visualizing arcs. To flip the clockwiseness of an arc, just switching the angles is enough. Negating them is not correct. This suggests an issue with the Arc format of all clockwise arcs