Fix crash in TimelineFragment (#2317)

app/src/main/java/com/keylesspalace/tusky/components/timeline/TimelineFragment.kt

@@ -208,12 +208,14 @@ class TimelineFragment :
             override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
                 if (positionStart == 0 && adapter.itemCount != itemCount) {
                     binding.recyclerView.post {
+                        if (getView() != null) {
                             if (isSwipeToRefreshEnabled) {
                                 binding.recyclerView.scrollBy(0, Utils.dpToPx(requireContext(), -30))
                             } else binding.recyclerView.scrollToPosition(0)
                         }
                     }
                 }
+            }
         })
 
         lifecycleScope.launch {