don't call methods on fake root node

Author: alex-courtis

lua/nvim-tree/actions/fs/clipboard.lua

@@ -217,9 +217,10 @@ end
 ---@param action ACTION
 ---@param action_fn fun(source: string, dest: string)
 function Clipboard:do_paste(node, action, action_fn)
-  node = node:last_group_node()
   if node.name == ".." then
     node = self.explorer
+  else
+    node = node:last_group_node()
   end
   local clip = self.data[action]
   if #clip == 0 then