Fix the issue that listener event is not triggered after calling UpdateChildren()

The issue is
1. The listener event will not be triggered if there is any pending writes requests
2. The pending writes record was not removed properly because UserWriteRecord is std::moved and WriteTree::RemoveWrite() still need it.

PiperOrigin-RevId: 277964067

Author: chkuang-g

database/src/desktop/core/sync_tree.cc

@@ -53,8 +53,8 @@ std::vector<Event> SyncTree::AckUserWrite(WriteId write_id, AckStatus revert,
     if (persist) {
       this->persistence_manager_->RemoveUserWrite(write_id);
     }
-    // Need to move the write out, as it is about to be deleted.
-    UserWriteRecord write = std::move(*pending_write_tree_->GetWrite(write_id));
+    // Make a copy of the write, as it is about to be deleted.
+    UserWriteRecord write = *pending_write_tree_->GetWrite(write_id);
     bool need_to_reevaluate = pending_write_tree_->RemoveWrite(write_id);
     if (write.visible) {
       if (!revert) {