Fix T90248: missing depsgraph update tag for node group

The code assumed that when a node group is is at the highest
level in the node editor, then it is embedded into another data
block and can't be referenced by other node groups. This is true
for shader and compositor nodes, but not for geometry nodes.

source/blender/editors/space_node/node_edit.cc

@@ -398,7 +398,7 @@ void snode_dag_update(bContext *C, SpaceNode *snode)
   Main *bmain = CTX_data_main(C);
 
   /* for groups, update all ID's using this */
-  if (snode->edittree != snode->nodetree) {
+  if ((snode->edittree->id.flag & LIB_EMBEDDED_DATA) == 0) {
     FOREACH_NODETREE_BEGIN (bmain, tntree, id) {
       if (ntreeHasTree(tntree, snode->edittree)) {
         DEG_id_tag_update(id, 0);