Fix T101872: Curves sculpt deform node crash with changed curve count

There might be more or fewer curves in the input to the deform curves on
surface node than the original, so the curve's surface UV coordinates
need to be retrieved from the original curves.

source/blender/nodes/geometry/nodes/node_geo_deform_curves_on_surface.cc

@@ -379,19 +379,22 @@ static void node_geo_exec(GeoNodeExecParams params)
                   invalid_uv_count);
     /* Then also deform edit curve information for use in sculpt mode. */
     const CurvesGeometry &curves_orig = CurvesGeometry::wrap(edit_hints->curves_id_orig.geometry);
-    deform_curves(curves_orig,
-                  *surface_mesh_orig,
-                  *surface_mesh_eval,
-                  surface_uv_coords,
-                  reverse_uv_sampler_orig,
-                  reverse_uv_sampler_eval,
-                  corner_normals_orig,
-                  corner_normals_eval,
-                  rest_positions,
-                  transforms.surface_to_curves,
-                  edit_hint_positions,
-                  edit_hint_rotations,
-                  invalid_uv_count);
+    const Span<float2> surface_uv_coords_orig = curves_orig.surface_uv_coords();
+    if (!surface_uv_coords_orig.is_empty()) {
+      deform_curves(curves_orig,
+                    *surface_mesh_orig,
+                    *surface_mesh_eval,
+                    surface_uv_coords_orig,
+                    reverse_uv_sampler_orig,
+                    reverse_uv_sampler_eval,
+                    corner_normals_orig,
+                    corner_normals_eval,
+                    rest_positions,
+                    transforms.surface_to_curves,
+                    edit_hint_positions,
+                    edit_hint_rotations,
+                    invalid_uv_count);
+    }
   }
 
   curves.tag_positions_changed();