Fix edge cases in conversation view.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -2902,7 +2902,6 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                 case YapDatabaseViewChangeDelete: {
                     DDLogVerbose(@"YapDatabaseViewChangeDelete: %@, %@", rowChange.collectionKey, rowChange.indexPath);
                     [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
-                    [rowsThatChangedSize removeObject:@(rowChange.indexPath.row)];
                     YapCollectionKey *collectionKey = rowChange.collectionKey;
                     OWSAssert(collectionKey.key.length > 0);
                     break;
@@ -2930,6 +2929,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                         rowChange.newIndexPath);
                     [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
                     [self.collectionView insertItemsAtIndexPaths:@[ rowChange.newIndexPath ]];
+                    [rowsThatChangedSize removeObject:@(rowChange.newIndexPath.row)];
                     break;
                 }
                 case YapDatabaseViewChangeUpdate: {
@@ -2947,7 +2947,9 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
         for (NSNumber *row in rowsThatChangedSize) {
             [rowsToReload addObject:[NSIndexPath indexPathForRow:row.integerValue inSection:0]];
         }
+        if (rowsToReload.count > 0) {
             [self.collectionView reloadItemsAtIndexPaths:rowsToReload];
+        }
     };
     void (^batchUpdatesCompletion)(BOOL) = ^(BOOL finished) {
         OWSAssert([NSThread isMainThread]);