The short answer is no. In general, it is not a desired behavior to have a new page load when you are clicking a tree-menu item that is meant to expand to show sub pages. Also, it is unlikely the visitor would need both
the expanded menu and
the page showing sub pages, so why offer duplicate methods at the cost of poor UI.
Instead, you could consider disabling the child items in the menu, so that the visitor has a simpler menu, and can click the parent menu to load the page which then lists the child pages. To achieve this, you would set in the parent folder:
Unlike the mega menu or dropdown menus based on hover, this is a limitation of a vertical tree menu.