Based on #5947

This PR refactors the Hexa2TetraTopologicalMapping to improve its readability and maintainability. It introduces static arrays for defining tetrahedron patterns and uses loops with these patterns for creating tetrahedra, replacing explicit individual calls. The commit also adds comprehensive unit tests to ensure the correct functionality of the mapping, including edge swapping logic and various grid configurations. These changes aim to make the code more robust and easier to understand.

Here's a list of the main changes:

• Refactoring of :Hexa2TetraTopologicalMapping.cpp The code has been cleaned up by replacing explicit vertex swapping for X, Y, and Z edges with loops iterating over sofa::geometry::Hexahedron::xEdges, yEdges, and zEdges. The direct addition of tetrahedra has also been refactored to use predefined patterns, improving readability.

• Introduction of Test Cases: New unit tests have been added in Hexa2TetraTopologicalMapping_test.cpp to cover various aspects of the mapping, including:

  • Handling of invalid inputs.
  • Verification of tetrahedron counts for different grid sizes.
  • Consistency of vertex counts between input hexahedra and output tetrahedra.
  • Testing the swapping parameter.
  • Ensuring tetrahedron vertex indices are valid.
  • Consistency of local-to-global mapping.
  • Specific output verification for single hexahedra with and without swapping.
  • Verification that all tetrahedron vertices belong to their source hexahedron.
  • Checking for degenerate tetrahedra.

• Enhancements to :Hexahedron.h Static constant arrays (xEdges, yEdges, zEdges) have been added to Hexahedron.h to define the edges along each axis, which are then used in the mapping logic.

[with-all-tests]

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• it does not break API compatibility.
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