**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
```
Poco::Logger * logger,
    ContextPtr local_context,
    const String & metadata_file_path,
    bool throw_on_error ,
    bool remove_empty )
{
    String query;
    try
    {
        ReadBufferFromFile in(metadata_file_path, METADATA_FILE_BUFFER_SIZE);
        readStringUntilEOF(query, in);
    }
    catch (const Exception & e)
    {
        if (!throw_on_error && e.code() == ErrorCodes::FILE_DOESNT_EXIST)
            return nullptr;
        else
            throw;
    }
    /** Empty files with metadata are generated after a rough restart of the server.
      * Remove these files to slightly reduce the work of the admins on startup.
      */
    if (remove_empty && query.empty())
    {
        if (logger)
            LOG_ERROR(logger, "File {} is empty. Removing.", metadata_file_path);