This fixes T103559, as described by @PratikPB2123.The issue was that the particle spawner mesh had no polygons/faces, The issue was that the particle spawner mesh had no polygons/faces, resulting in
a NullPointerException in `mfaces`. This diffSo checks for such cases where the mesh has no polygons,
and if present silently hides that the CD_MFACE layer is not being generated from CD_MPOLY as it should be.