[Tests] Factorize code and add new tests on adding/removing triangles in TriangleSetTopology_test

[epernod]

1 issue to be created:
Test testAddingTriangles reveal that method
testAddingTriangles is crashing. Check:

    // TODO @epernod (2025-01-28): Adding the triangle create a segmentation fault. Need to investigate why
    // triangleModifier->addTriangles(triangesToAdd);

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• it builds with SUCCESS for all platforms on the CI.
• it does not generate new warnings.
• it does not generate new unit test failures.
• it does not generate new scene test failures.
• it does not break API compatibility.
• it is more than 1 week old (or has fast-merge label).

[epernod]

[ci-build][with-all-tests]