Fix (unreported) bad handling of embedded IDs on owner copying.

Completely forgot in rBcd49fee74114 to handle the owner ID copying case
(this code now also needs to re-assign to `owner_id` pointer of the
newly copied embedded IDs to their rightful owner).

source/blender/blenkernel/intern/light.c

@@ -80,6 +80,7 @@ static void light_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
       BKE_id_copy_ex(
           bmain, (ID *)la_src->nodetree, (ID **)&la_dst->nodetree, flag_private_id_data);
     }
+    la_dst->nodetree->owner_id = &la_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {

source/blender/blenkernel/intern/linestyle.c

@@ -72,6 +72,7 @@ static void linestyle_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
                    (ID *)linestyle_src->nodetree,
                    (ID **)&linestyle_dst->nodetree,
                    flag_private_id_data);
+    linestyle_dst->nodetree->owner_id = &linestyle_dst->id;
   }
 
   LineStyleModifier *linestyle_modifier;

source/blender/blenkernel/intern/material.c

@@ -102,6 +102,7 @@ static void material_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
                      (ID **)&material_dst->nodetree,
                      flag_private_id_data);
     }
+    material_dst->nodetree->owner_id = &material_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {

source/blender/blenkernel/intern/scene.cc

@@ -250,6 +250,7 @@ static void scene_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
                    (ID *)scene_src->master_collection,
                    (ID **)&scene_dst->master_collection,
                    flag_private_id_data);
+    scene_dst->master_collection->owner_id = &scene_dst->id;
   }
 
   /* View Layers */
@@ -275,6 +276,7 @@ static void scene_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
                            (void *)(&scene_src->id),
                            &scene_dst->id,
                            ID_REMAP_SKIP_NEVER_NULL_USAGE | ID_REMAP_SKIP_USER_CLEAR);
+    scene_dst->nodetree->owner_id = &scene_dst->id;
   }
 
   if (scene_src->rigidbody_world) {

source/blender/blenkernel/intern/simulation.cc

@@ -67,6 +67,7 @@ static void simulation_copy_data(Main *bmain, ID *id_dst, const ID *id_src, cons
                    (ID *)simulation_src->nodetree,
                    (ID **)&simulation_dst->nodetree,
                    flag_private_id_data);
+    simulation_dst->nodetree->owner_id = &simulation_dst->id;
   }
 }
 

source/blender/blenkernel/intern/texture.c

@@ -96,6 +96,7 @@ static void texture_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const i
       BKE_id_copy_ex(
           bmain, (ID *)texture_src->nodetree, (ID **)&texture_dst->nodetree, flag_private_id_data);
     }
+    texture_dst->nodetree->owner_id = &texture_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {

source/blender/blenkernel/intern/world.c

@@ -98,6 +98,7 @@ static void world_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
       BKE_id_copy_ex(
           bmain, (ID *)wrld_src->nodetree, (ID **)&wrld_dst->nodetree, flag_private_id_data);
     }
+    wrld_dst->nodetree->owner_id = &wrld_dst->id;
   }
 
   BLI_listbase_clear(&wrld_dst->gpumaterial);