feat: Implement can request history calculation

lib/src/timeline.dart

@@ -68,6 +68,11 @@ class Timeline {
   bool _collectHistoryUpdates = false;
   final Set<EventUpdate> _historyUpdates = <EventUpdate>{};
 
+  bool get canRequestHistory {
+    if (events.isEmpty) return true;
+    return events.last.type != EventTypes.RoomCreate;
+  }
+
   Future<void> requestHistory(
       {int historyCount = Room.DefaultHistoryCount}) async {
     if (!isRequestingHistory) {

test/timeline_test.dart

@@ -283,6 +283,7 @@ void main() {
 
     test('Request history', () async {
       timeline.events.clear();
+      expect(timeline.canRequestHistory, true);
       await room.requestHistory();
 
       await Future.delayed(Duration(milliseconds: 50));