Tet remeshing - improve surface approximation

[janetournois]

Summary of Changes

In areas where the surface has a high curvature but no feature edge is protected, tetrahedral remeshing tends to shrink the volume and increase the surface approximation error, as shown here :

The flipping step is responsible for that shrink, and this PR is meant to fix this issue.

Release Management

• Affected package(s): Tetrahedral remeshing
• License and copyright ownership: unchanged