**How to reproduce**
Clickhouse version 21.5

```
cat /etc/clickhouse-server/users.xml
<?xml version="1.0"?>
<yandex>
    <!-- Profiles of settings. -->
    <profiles>
        <!-- Default settings. -->
        <default>
            <data_type_default_nullable>1</data_type_default_nullable>
            <load_balancing>random</load_balancing>
        </default>
....

2021.04.04 01:23:42.453678 [ 29048 ] {} <Error> Application: DB::Exception: Nested type Array(UInt64) cannot be inside Nullable type: Cannot attach table `system`.`crash_log` from metadata file /var/lib/clickhouse/metadata/system/crash_log.sql from query ATTACH TABLE system.crash_log (`event_date` Date, `event_time` DateTime, `timestamp_ns` UInt64, `signal` Int32, `thread_id` UInt64, `query_id` String, `trace` Array(UInt64), `trace_full` Array(String), `version` String, `revision` UInt32, `build_id` String) ENGINE = MergeTree ORDER BY (event_date, event_time) SETTINGS index_granularity = 8192: while loading database `system` from path /var/lib/clickhouse/metadata/system
```
if (!table)
        return;
    bool renamed = false;
    try
    {
        Poco::File(table_metadata_path).renameTo(table_metadata_path_drop);
        renamed = true;
        table->drop();
        table->is_dropped = true;
        Poco::File table_data_dir{local_context->getPath() + table_data_path_relative};
        if (table_data_dir.exists())
            table_data_dir.remove(true);
    }
    catch (...)
    {
        LOG_WARNING(log, getCurrentExceptionMessage(__PRETTY_FUNCTION__));
        attachTable(table_name, table, table_data_path_relative);
        if (renamed)
            Poco::File(table_metadata_path_drop).renameTo(table_metadata_path);
        throw;
    }
    Poco::File(table_metadata_path_drop).remove();
}
void DatabaseOnDisk::checkMetadataFilenameAvailability(const String & to_table_name) const
{
    std::unique_lock lock(mutex);
    checkMetadataFilenameAvailabilityUnlocked(to_table_name, lock);
}
void DatabaseOnDisk::checkMetadataFilenameAvailabilityUnlocked(const String & to_table_name, std::unique_lock<std::mutex> &) const