**Describe the unexpected behaviour**
ClickHouse returns exception if you would try to read polygon dictionary via SELECT query.

**How to reproduce**
ClickHouse version 21.10


```
CREATE DICTIONARY polygon_dict (
    key Array(Array(Array(Array(Float64)))),
    name String,
    value UInt64
)
PRIMARY KEY key
LAYOUT(POLYGON())
SOURCE(CLICKHOUSE(table 'polygon_dict_src'))
LIFETIME(MIN 300 MAX 360);

CREATE TABLE polygon_dict_src
(
    `key` Array(Array(Array(Array(Float64)))),
    `name` String,
    `value` UInt64
)
ENGINE = Log
	
INSERT INTO polygon_dict_src SELECT [[[[1.1,2.1],[5,3],[6,4],[1,4]]]], 'some', 10;


CREATE DICTIONARY polygon_dict (
    key Array(Array(Array(Array(Float64)))),
    name String,
    value UInt64
)
PRIMARY KEY key
LAYOUT(POLYGON())
SOURCE(CLICKHOUSE(table 'polygon_dict_src'))
LIFETIME(MIN 300 MAX 360);

SELECT dictGet(polygon_dict, 'name', (2., 3.)) AS x

┌─x────┐
│ some │
└──────┘

SELECT *
FROM polygon_dict

0 rows in set. Elapsed: 0.008 sec.

Received exception from server (version 21.10.1):
Code: 1. DB::Exception: Received from localhost:9000. DB::Exception: Reading the dictionary is not allowed. (UNSUPPORTED_METHOD)
```


**Expected behavior**
It's allowed to read POLYGON dictionaries via SELECT query.

requested_key_points,
                    [&](size_t row) { return attribute_data[row]; },
                    [&](auto value) { result_data.emplace_back(value); },
                    default_value_provider);
            }
        };
        callOnDictionaryAttributeType(attribute.underlying_type, type_call);
    }
    return result;
}
Pipe IPolygonDictionary::read(const Names &, size_t) const
{
    
    
    throw Exception(ErrorCodes::UNSUPPORTED_METHOD, "Reading the dictionary is not allowed");
}
void IPolygonDictionary::setup()
{
    attributes.reserve(dict_struct.attributes.size());
    for (const auto & attribute : dict_struct.attributes)
    {
        auto column = attribute.type->createColumn();
        attributes.emplace_back(std::move(column));
        if (attribute.hierarchical)
            throw Exception(ErrorCodes::TYPE_MISMATCH,
                            "{}: hierarchical attributes not supported for dictionary of polygonal type",
                            getDictionaryID().getNameForLogs());
    }
}
void IPolygonDictionary::blockToAttributes(const DB::Block & block)