DEMO ONLY: showcase potential fix

Author: gagik

src/realm/object-store/sync/sync_manager.cpp

@@ -391,7 +391,7 @@ void SyncManager::close_all_sessions()
     }
 
     for (auto& [_, session] : sessions) {
-        session->force_close();
+        session->shutdown_and_wait();
     }
 
     get_sync_client().wait_for_session_terminations();