Add triangle_math tests and fix Triangle3d::bounding_sphere bug

[vitorfhc]

Objective

To test and fix the Triangle3d methods.

Solution

• Fixes an issue with the Triangle3d::bounding_sphere method, which was not translating the sphere to the largest side mid-point.
• Add tests for the Triangle3d math.

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Changelog

Changed

• Add Triangle3d tests
• Fix Triangle3d::bounding_sphere bug for degenerate triangles