Fix #108719: correct link is shown as invalid

The issue was that the links was tagged as invalid for one render engine,
because it does not support the output pass. However, switching back
to Cycles did not make the link valid again.

source/blender/editors/render/render_update.cc

@@ -201,6 +201,7 @@ void ED_render_engine_changed(Main *bmain, const bool update_scene_data)
       ntreeCompositUpdateRLayers(scene->nodetree);
     }
   }
+  ED_node_tree_propagate_change(nullptr, bmain, nullptr);
 
   /* Update #CacheFiles to ensure that procedurals are properly taken into account. */
   LISTBASE_FOREACH (CacheFile *, cachefile, &bmain->cachefiles) {