PLY: Fix export faces with more than 255 sides

Ideally we want to use uint16 or uint32 data type for this purpose,
but certain DCCs have hardcoded uint8 limits in their PLY importers.

Silently tringulating faces with many sides is bad, but it's even worse
when correctly exported model won't load because of poor importer
implementation in other DCCs.

io_mesh_ply/export_ply.py

@@ -244,6 +244,10 @@ def save(
         bm.from_mesh(me)
         ob_eval.to_mesh_clear()
 
+    # Workaround for hardcoded unsigned char limit in other DCCs PLY importers
+    if (ngons := [f for f in bm.faces if len(f.verts) > 255]):
+        bmesh.ops.triangulate(bm, faces=ngons)
+
     mesh = bpy.data.meshes.new("TMP PLY EXPORT")
     bm.to_mesh(mesh)
     bm.free()