Fix: Failing test after combination of Mesh refactors

The mesh positions are now a span, but the convex hull didn't copy
the custom data layout to the new mesh since it assumed it didn't
need to. Moving UV maps to a generic attribute triggers this difference
in the test results.

It doesn't really make sense for the convex hull node to copy the
source mesh custom data layout at all anyway, but do it anyway
to avoid having to change the tests right now.

source/blender/nodes/geometry/nodes/node_geo_convex_hull.cc

@@ -183,7 +183,7 @@ static Mesh *compute_hull(const GeometrySet &geometry_set)
   /* If there is only one positions virtual array and it is already contiguous, avoid copying
    * all of the positions and instead pass the span directly to the convex hull function. */
   if (span_count == 1 && count == 1) {
-    return hull_from_bullet(nullptr, positions_span);
+    return hull_from_bullet(geometry_set.get_mesh_for_read(), positions_span);
   }
 
   Array<float3> positions(total_num);