**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
```
data_path = (user_files / data_path).lexically_normal();
            if (!startsWith(data_path, user_files))
                throw Exception(ErrorCodes::PATH_ACCESS_DENIED,
                                "Data directory {} must be inside {} to attach it", String(data_path), String(user_files));
            
            create.attach_from_path = fs::relative(data_path, root_path) / "";
        }
        else
        {
            fs::path data_path = (root_path / *create.attach_from_path).lexically_normal();
            if (!startsWith(data_path, user_files))
                throw Exception(ErrorCodes::PATH_ACCESS_DENIED,
                                "Data directory {} must be inside {} to attach it", String(data_path), String(user_files));
        }
    }
    else if (create.attach && !create.attach_short_syntax && getContext()->getClientInfo().query_kind != ClientInfo::QueryKind::SECONDARY_QUERY)
    {
        auto * log = &Poco::Logger::get("InterpreterCreateQuery");
        LOG_WARNING(log, "ATTACH TABLE query with full table definition is not recommended: "
                         "use either ATTACH TABLE {}; to attach existing table "
                         "or CREATE TABLE {} <table definition>; to create new table "
                         "or ATTACH TABLE {} FROM '/path/to/data/' <table definition>; to create new table and attach data.",
                         create.table, create.table, create.table);
    }
    if (!create.temporary && create.database.empty())
        create.database = current_database;
    if (create.to_table_id && create.to_table_id.database_name.empty())
        create.to_table_id.database_name = current_database;
    if (create.select && create.isView())
    {