Fix #108049: Nodes pasting can leave multiple active nodes

Clear active flag on pasted nodes (this is in line with how objects are
pasted).

Pull Request: https://projects.blender.org/blender/blender/pulls/108535

source/blender/editors/space_node/clipboard.cc

@@ -276,6 +276,8 @@ static int node_clipboard_paste_exec(bContext *C, wmOperator *op)
   for (bNode *new_node : node_map.values()) {
     nodeSetSelected(new_node, true);
 
+    new_node->flag &= ~NODE_ACTIVE;
+
     /* The parent pointer must be redirected to new node. */
     if (new_node->parent) {
       if (node_map.contains(new_node->parent)) {