UITabbarController show space above navigationbar ios15

**Describe the bug**
When adding UITbbarController in viewcontroller stack of AMScrollNavBar.The top space does'nt go away.

**To Reproduce**
Steps to reproduce the behavior:
1. Adding tabbarcontroller to navigation bar like this `self.navigationController?.viewControllers = [UIStoryboard.main.instantiateViewController(withIdentifier: TabbarViewController.className)]` and navigationcontroller is ScrollingNavigationViewController.
2. Child controllers of tabbarcontroller shows space above navigationbar.
3. I'm using ios version 15.Xcode version 13.1.Macos version 11.6

**Expected behavior**
These top space should not be visible.

**Screenshots**

Start by reproducing the issue on iOS 15 with a ScrollingNavigationViewController whose viewControllers contains the reported UITabbarController setup. Inspect the AMScrollNavBar navigation-bar behavior around the tab bar's child controllers; done means the unwanted space above the navigation bar is no longer visible.

Written by the indexing model from the issue text.