Provision to handle 3rd or more level menu

Problem/Motivation

Currently, the navigation menu operates effectively up to the second level only.

Steps to reproduce

Create a menu with three level

Services
- Taxation
-- Team
-- Reviews

Despite having set the "Show as expanded" option for the "Taxation" item in the menu, and configuring an appropriate value in the "Number of levels to display" field under the navigation block settings, the sub-menus for the Taxation team and reviews are not appearing when hovered over.

However, the HTML markup does contain the sub-menu. Please find attached the relevant screenshots for reference.