Fix retain cycle in GutenbergViewController (#22265)

RELEASE-NOTES.txt

@@ -4,6 +4,7 @@
 * [***] [Jetpack-only] Plans: Upgrade to a WPCOM plan from domains dashboard in Jetpack app. [#22261]
 * [**] [internal] Refactor domain selection flows to use the same domain selection UI. [22254]
 * [**] Re-enable the support for using Security Keys as a second factor during login [#22258]
+* [*] Fix crash in editor that sometimes happens after modifying tags or categories [#22265]
 
 23.9
 -----

WordPress/Classes/ViewRelated/Post/Prepublishing/PrepublishingViewController.swift

@@ -47,9 +47,9 @@ class PrepublishingViewController: UITableViewController {
         return PublishSettingsViewModel(post: post)
     }()
 
-    private lazy var presentedVC: DrawerPresentationController? = {
+    private var presentedVC: DrawerPresentationController? {
         return (navigationController as? PrepublishingNavigationController)?.presentedVC
-    }()
+    }
 
     enum CompletionResult {
         case completed(AbstractPost)
@@ -133,13 +133,11 @@ class PrepublishingViewController: UITableViewController {
     /// Toggles `keyboardShown` as the keyboard notifications come in
     private func configureKeyboardToggle() {
         NotificationCenter.default.publisher(for: UIResponder.keyboardDidShowNotification)
-            .map { _ in return true }
-            .assign(to: \.keyboardShown, on: self)
+            .sink { [weak self] _ in self?.keyboardShown = true }
             .store(in: &cancellables)
 
         NotificationCenter.default.publisher(for: UIResponder.keyboardDidHideNotification)
-            .map { _ in return false }
-            .assign(to: \.keyboardShown, on: self)
+            .sink { [weak self] _ in self?.keyboardShown = false }
             .store(in: &cancellables)
     }