Revert "refactor(#2871, #2886): multi instance: node classes created (#2916)"

This reverts commit 38aac09151.

lua/nvim-tree/actions/tree/modifiers/expand-all.lua

@@ -1,6 +1,7 @@
 local core = require("nvim-tree.core")
 local Iterator = require("nvim-tree.iterators.node-iterator")
 local notify = require("nvim-tree.notify")
+local lib = require("nvim-tree.lib")
 
 local M = {}
 
@@ -17,7 +18,7 @@ end
 
 ---@param node Node
 local function expand(node)
-  node = node:last_group_node()
+  node = lib.get_last_group_node(node)
   node.open = true
   if #node.nodes == 0 then
     core.get_explorer():expand(node)
@@ -61,10 +62,10 @@ local function gen_iterator()
   end
 end
 
----@param node Node
-function M.fn(node)
+---@param base_node table
+function M.fn(base_node)
   local explorer = core.get_explorer()
-  node = node.nodes and node or explorer
+  local node = base_node.nodes and base_node or explorer
   if gen_iterator()(node) then
     notify.warn("expansion iteration was halted after " .. M.MAX_FOLDER_DISCOVERY .. " discovered folders")
   end