"touch" expires and replication

Certain data structures, namely the `DenseSet` expires values while `traversing`. This in practice means, that an expired member won't really expire unless another command on the same key "touches" it.

We had a bug here https://github.com/dragonflydb/dragonfly/pull/4873/files#r2032946766 that we basically expired the `key` because it became empty but we never submitted its deletion to the journal. Consequently, master had this key expired and replica did not. We should:

1. Check all flows that have "delayed expirations" and delete the key when the data structure becomes empty
2. Add replication tests for consistency

Start by tracing the DenseSet traversal path and every flow with delayed expirations, using the linked pull request as context for the prior replication bug. Add replication coverage for empty data structures and verify that master and replica delete the same expired keys.

Written by the indexing model from the issue text.