Wait for rooms and account data to load

lib/zenith_client_provider.dart

@@ -20,6 +20,8 @@ class ZenithClientProvider extends ChangeNotifier {
       await client.login(LoginType.mLoginPassword,
           identifier: AuthenticationUserIdentifier(user: username),
           password: password);
+      await client.roomsLoading;
+      await client.accountDataLoading;
     } finally {
       _loading = false;
     }