**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.

{
    Data data = {polygons, polygon_index_to_attribute_value_index};
    Offset offset;
    const IColumn * points_collection = nullptr;
    switch (input_type)
    {
        case InputType::MultiPolygon:
            points_collection = unrollMultiPolygons(column, offset);
            break;
        case InputType::SimplePolygon:
            points_collection = unrollSimplePolygons(column, offset);
            break;
    }
    if (!offset.allRingsHaveAPositiveArea())
        throw Exception(ErrorCodes::BAD_ARGUMENTS,
            "Every ring included in a polygon or excluded from it should contain at least 3 points");
    
    data.addPolygon(true);
    switch (point_type)
    {
        case PointType::Array:
            handlePointsReprByArrays(points_collection, data, offset);
            break;
        case PointType::Tuple:
            handlePointsReprByTuples(points_collection, data, offset);
            break;
    }
}
}