handle if lastEvent is null

lib/components/list_items/chat_list_item.dart

@@ -184,16 +184,17 @@ class ChatListItem extends StatelessWidget {
                         softWrap: false,
                       )
                     : Text(
-                        room.lastEvent.getLocalizedBody(
+                        room.lastEvent?.getLocalizedBody(
                               L10n.of(context),
                               withSenderNamePrefix: !room.isDirectChat,
                               hideReply: true,
-                        ),
+                            ) ??
+                            '',
                         softWrap: false,
                         maxLines: 1,
                         overflow: TextOverflow.fade,
                         style: TextStyle(
-                          decoration: room.lastEvent.redacted
+                          decoration: room.lastEvent?.redacted == true
                               ? TextDecoration.lineThrough
                               : null,
                         ),

lib/views/chat_list.dart

@@ -384,10 +384,11 @@ class _ChatListState extends State<ChatList> {
                               var rooms = List<Room>.from(
                                   Matrix.of(context).client.rooms);
                               rooms.removeWhere((Room room) =>
-                                  searchMode &&
+                                  room.lastEvent == null ||
+                                  (searchMode &&
                                       !room.displayname.toLowerCase().contains(
                                           searchController.text.toLowerCase() ??
-                                          ''));
+                                              '')));
                               if (rooms.isEmpty &&
                                   (!searchMode ||
                                       publicRoomsResponse == null)) {