With migration 77, I had a huge misunderstanding about the new migration approach. I thought for this migration we needed to create and directly return a new thread store to redux using `.processStoreOperations()`. However, we actually should only just return the operations and just return `state` as is. The `threadStore` will be read by `SQLiteDataHandler` which populates redux with the migrated data from the ops.
Anyways, we need this function for both `native` + `web` migrations, this diff lifts this function into `lib`
Depends on D12497