Avoid crash if activity is already dead

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt

@@ -217,7 +217,7 @@ class LibraryController(
             }
             .launchIn(viewScope)
 
-        (activity!! as MainActivity).fixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.fixViewToBottom(binding.actionToolbar)
     }
 
     override fun onChangeStarted(handler: ControllerChangeHandler, type: ControllerChangeType) {
@@ -230,7 +230,7 @@ class LibraryController(
 
     override fun onDestroyView(view: View) {
         destroyActionModeIfNeeded()
-        (activity!! as MainActivity).clearFixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.clearFixViewToBottom(binding.actionToolbar)
         binding.actionToolbar.destroy()
         adapter?.onDestroy()
         adapter = null

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -242,7 +242,7 @@ class MangaController :
             }
             .launchIn(viewScope)
 
-        (activity!! as MainActivity).fixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.fixViewToBottom(binding.actionToolbar)
 
         settingsSheet = ChaptersSettingsSheet(router, presenter) { group ->
             if (group is ChaptersSettingsSheet.Filter.FilterGroup) {
@@ -321,7 +321,7 @@ class MangaController :
 
     override fun onDestroyView(view: View) {
         destroyActionModeIfNeeded()
-        (activity!! as MainActivity).clearFixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.clearFixViewToBottom(binding.actionToolbar)
         binding.actionToolbar.destroy()
         mangaInfoAdapter = null
         chaptersHeaderAdapter = null

app/src/main/java/eu/kanade/tachiyomi/ui/recent/updates/UpdatesController.kt

@@ -109,12 +109,12 @@ class UpdatesController :
             }
             .launchIn(viewScope)
 
-        (activity!! as MainActivity).fixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.fixViewToBottom(binding.actionToolbar)
     }
 
     override fun onDestroyView(view: View) {
         destroyActionModeIfNeeded()
-        (activity!! as MainActivity).clearFixViewToBottom(binding.actionToolbar)
+        (activity as? MainActivity)?.clearFixViewToBottom(binding.actionToolbar)
         binding.actionToolbar.destroy()
         adapter = null
         super.onDestroyView(view)