Fix #5636: Invalidate NTP layout when sections change to fix News layout

On first launches default favourites are added async which cause FRCs to fire after NTP is already laid out, which trigger `sectionDidChange`. When this happens we were reloading the changed sections without animation but this would sometimes cause layout issues with sections not reloaded like Brave News.

Client/Frontend/Browser/New Tab Page/NewTabPageViewController.swift

@@ -279,6 +279,7 @@ class NewTabPageViewController: UIViewController {
           UIView.performWithoutAnimation {
             self?.collectionView.reloadSections(IndexSet(integer: index))
           }
+          self?.collectionView.collectionViewLayout.invalidateLayout()
         }
       }
     }