GetFaceUV is not stable --> Some cells cannot be generated

[joergbrech]

We recently hat performance issues with the cell geometry generation, because the cell geometries were always cut, even when the resulting shape is just a trimmed surface. For this reason, even if the cell borders are not defined using contour coordinates, it is first checked if the cell can be trimmed rather than cut. To do this we project the corner points defined on the chordface onto the wing shell and identify the associated face and (u,v) coordinate on that point. This fails sometimes.

In this case, we should not throw an error, but fall back to the cutting algorithm.

[joergbrech]

@hardt-fa-flb, pinging you here.