**How to reproduce**
Clickhouse server 20.13.1.5273
```
CREATE TABLE default.test
(
`key` UInt32,
`ts` DateTime CODEC(DoubleDelta, LZ4),
`db_time` DateTime DEFAULT now() COMMENT 'spout-ignore' CODEC(DoubleDelta, LZ4)
)
ENGINE = MergeTree
PARTITION BY toStartOfTenMinutes(db_time)
ORDER BY (key, ts)
TTL db_time + toIntervalHour(3)
SETTINGS index_granularity = 8192, merge_with_ttl_timeout = 3600, min_rows_for_compact_part = 1000000, min_bytes_for_compact_part = 200000000, in_memory_parts_enable_wal = 0;


INSERT INTO test(key, ts) SELECT number % 1000, now() + intDiv(number,1000) FROM numbers(500);

SELECT * FROM test;
500 rows in set. Elapsed: 0.003 sec.

DETACH TABLE test;

ATTACH TABLE test;

SELECT * FROM test;

0 rows in set. Elapsed: 0.002 sec.
```

**Expected behavior**
Clickhouse would flush parts on disk.
{
    auto metadata_snapshot = getInMemoryMetadataPtr();
    if (detach)
    {
        
        
        for (const auto & part : parts_to_remove)
        {
            LOG_INFO(log, "Detaching {}", part->relative_path);
            part->makeCloneInDetached("", metadata_snapshot);
        }
    }
    if (deduplication_log)
    {
        for (const auto & part : parts_to_remove)
            deduplication_log->dropPart(part->info);
    }
    if (detach)
        LOG_INFO(log, "Detached {} parts.", parts_to_remove.size());
    else
        LOG_INFO(log, "Removed {} parts.", parts_to_remove.size());
    
    parts_to_remove.clear();
    clearOldPartsFromFilesystem();
}
PartitionCommandsResultInfo StorageMergeTree::attachPartition(