Looks like https://github.com/ClickHouse/ClickHouse/pull/21303 is broke also "clear column" for such columns.

How to reproduce:

```
CREATE TABLE test.TTAdmLog
(
    `ts` DateTime,
    `event_date` Date DEFAULT toDate(ts),
    `impression_id` String DEFAULT '',
    `creative_id` String DEFAULT '',
    `creative_adm` String DEFAULT '',
    `impression_id_compressed` FixedString(16) DEFAULT UUIDStringToNum(impression_id),
    `impression_id_hashed` UInt16 DEFAULT reinterpretAsUInt16(impression_id_compressed),
)
ENGINE = ReplicatedMergeTree('/clickhouse/tables/{shard}/TTAdmLogTest', '{replica}')
PARTITION BY toMonday(event_date)
ORDER BY (event_date, impression_id_hashed)
SAMPLE BY impression_id_hashed
SETTINGS replicated_deduplication_window = 1000, replicated_deduplication_window_seconds = 864000, index_granularity = 8192

CREATE MATERIALIZED VIEW test.TTView
(
    `event_date` Date,
    `creative_id` String,
    `creative_adm` AggregateFunction(anyLast, String),
)
ENGINE = ReplicatedAggregatingMergeTree('/clickhouse/tables/{shard}/TTViewTest', '{replica}', event_date, (event_date, creative_id), 8192) AS
SELECT 
    toStartOfMonth(event_date) AS event_date,
    arrayJoin(splitByChar(',', creative_id)) AS creative_id,
    anyLastState(creative_adm) AS creative_adm,
FROM test.TTAdmLog
GROUP BY 
    event_date,
    creative_id,

```


ClickHouse server version 20.9.3 revision 54439.

```
alter table test.TTAdmLog clear column creative_adm in partition '2021-03-22'

OK

```
ClickHouse server version 21.4.3 revision 54447.

```
alter table test.TTAdmLog  clear column creative_adm in partition '2021-03-22'

DB::Exception: Trying to ALTER DROP column creative_adm which is referenced by materialized view ['TTView'].

```

throw Exception(ErrorCodes::BAD_ARGUMENTS,
                "Cannot drop or clear column{} '{}', because all columns in part '{}' will be removed from disk. Empty parts are not allowed", postfix, boost::algorithm::join(dropped_columns, ", "), part->name);
        }
    }
}
void MergeTreeData::checkMutationIsPossible(const MutationCommands & , const Settings & ) const
{
    
}
MergeTreeDataPartType MergeTreeData::choosePartType(size_t bytes_uncompressed, size_t rows_count) const
{
    const auto settings = getSettings();
    if (!canUsePolymorphicParts(*settings))
        return MergeTreeDataPartType::WIDE;
    if (bytes_uncompressed < settings->min_bytes_for_compact_part || rows_count < settings->min_rows_for_compact_part)
        return MergeTreeDataPartType::IN_MEMORY;
    if (bytes_uncompressed < settings->min_bytes_for_wide_part || rows_count < settings->min_rows_for_wide_part)
        return MergeTreeDataPartType::COMPACT;
    return MergeTreeDataPartType::WIDE;
}
MergeTreeDataPartType MergeTreeData::choosePartTypeOnDisk(size_t bytes_uncompressed, size_t rows_count) const
{
    const auto settings = getSettings();
    if (!canUsePolymorphicParts(*settings))
        return MergeTreeDataPartType::WIDE;
    if (bytes_uncompressed < settings->min_bytes_for_wide_part || rows_count < settings->min_rows_for_wide_part)
        return MergeTreeDataPartType::COMPACT;
    return MergeTreeDataPartType::WIDE;
}
MergeTreeData::MutableDataPartPtr MergeTreeData::createPart(const String & name,