`vtkCurvature` didn't use to handle `vtkTriangleStrip` cells.
The Gauss curvature is computed by iterating on each triangle
of triangle strip cells. The mean curvature implementation
was less flexible, hence if there is at least one `vtkTriangleStrip`
in the input, the whole input is triangulated in a local
`vtkPolyData` prior to computing the mean curvature.

Adresses paraview/paraview#19767