fix(useTree.ts):修复tree-v2组件开启accordion模式后展开不了的问题 (#9591)

Co-authored-by: 罗宇 <luoyu10301>

packages/components/tree-v2/src/composables/useTree.ts

@@ -223,8 +223,8 @@ export function useTree(props: TreeProps, emit) {
       // whether only one node among the same level can be expanded at one time
       const { treeNodeMap } = tree.value
       keySet.forEach((key) => {
-        const node = treeNodeMap.get(key)
-        if (node && node.level === node.level) {
+        const treeNode = treeNodeMap.get(key)
+        if (node && node.level === treeNode.level) {
           keySet.delete(key)
         }
       })