Fix #114822: Data transfer modifier doesn't work for face corner normals

In 89e3ba4e25, the preprocess step was removed because the
normals are lazily calculated. But now we need to fetch the source normals
from the correct placed-- they still were looked for in `CD_NORMAL`.

source/blender/blenkernel/intern/data_transfer.cc

@@ -393,6 +393,7 @@ static void data_transfer_dtdata_type_postprocess(Mesh *me_dst,
                                                 {loop_nors_dst, me_dst->totloop},
                                                 {custom_nors_dst, me_dst->totloop});
     sharp_edges.finish();
+    CustomData_free_layers(ldata_dst, CD_NORMAL, me_dst->totloop);
   }
 }
 
@@ -1034,11 +1035,21 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       cddata_type = CD_PROP_FLOAT2;
     }
     else if (cddata_type == CD_FAKE_LNOR) {
-      /* Pre-process should have generated it,
-       * Post-process will convert it back to CD_CUSTOMLOOPNORMAL. */
-      cddata_type = CD_NORMAL;
-      interp_data = space_transform;
-      interp = customdata_data_transfer_interp_normal_normals;
+      if (!CustomData_get_layer(&me_dst->loop_data, CD_PROP_FLOAT)) {
+        CustomData_add_layer(&me_dst->loop_data, CD_NORMAL, CD_SET_DEFAULT, me_dst->totloop);
+      }
+      /* Post-process will convert it back to CD_CUSTOMLOOPNORMAL. */
+      data_transfer_layersmapping_add_item_cd(
+          r_map,
+          CD_NORMAL,
+          mix_mode,
+          mix_factor,
+          mix_weights,
+          me_src->corner_normals().data(),
+          CustomData_get_layer_for_write(&me_dst->loop_data, CD_NORMAL, me_dst->totloop),
+          customdata_data_transfer_interp_normal_normals,
+          space_transform);
+      return true;
     }
 
     if (!(cddata_type & CD_FAKE)) {