[代码优化](v2.6)：优化多级菜单之间切换无法缓存的问题

src/store/modules/permission.js

@@ -62,6 +62,7 @@ function filterChildren(childrenMap) {
           }
           children.push(c)
         })
+        childrenMap.splice(index, 1)
         return
       }
     }