Fix HomeViewController retain cycle (#2462)

Task/Issue URL: https://app.asana.com/0/414235014887631/1206561582798187/f
Tech Design URL:
CC:

Description:

This PR fixes an issue with every HomeViewController instance being affected by a retain cycle.

DuckDuckGo/HomeCollectionView.swift

@@ -85,8 +85,12 @@ class HomeCollectionView: UICollectionView {
 
             case .favorites:
                 let renderer = FavoritesHomeViewSectionRenderer(viewModel: favoritesViewModel)
-                renderer.onFaviconMissing = { _ in
-                    controller.faviconsFetcherOnboarding.presentOnboardingIfNeeded(from: controller)
+                renderer.onFaviconMissing = { [weak self] _ in
+                    guard let self else {
+                        return
+                    }
+
+                    self.controller.faviconsFetcherOnboarding.presentOnboardingIfNeeded(from: self.controller)
                 }
                 renderers.install(renderer: renderer)