Remove OOO Head compaction's dependency on the in-order Head compaction

Proposal

It is possible that the in-order Head stopped getting data for a while, while the OOO Head kept getting a lot of old data. In which case, we should compact the OOO data eventually.

Currently, we attempt OOO compaction only if the in-order Head gets compacted. We should remove that dependency to attempt OOO compaction every 2h as well. Irrespective of block duration here, we can attempt OOO compaction every 2h because there is no cap on how much OOO data you can ingest.