LibWeb: Implement most of upgrade_a_database for IndexedDB

Author: https://github.com/stelar7
Commit: 1656d8fe07
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2236
Reviewed-by: https://github.com/gmta ✅

Libraries/LibWeb/IndexedDB/Internal/Database.cpp

@@ -25,6 +25,7 @@ void Database::visit_edges(Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(m_associated_connections);
+    visitor.visit(m_upgrade_transaction);
 }
 
 ConnectionQueue& ConnectionQueueHandler::for_key_and_name(StorageAPI::StorageKey& key, String& name)