**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.

const DictionaryStructure & dict_struct,
                           const Poco::Util::AbstractConfiguration & config,
                           const std::string & config_prefix,
                           DictionarySourcePtr source_ptr,
                           ContextPtr ,
                           bool )
{
    const String database = config.getString(config_prefix + ".database", "");
    const String name = config.getString(config_prefix + ".name");
    if (!dict_struct.key)
        throw Exception(ErrorCodes::BAD_ARGUMENTS, "'key' is required for a polygon dictionary");
    if (dict_struct.key->size() != 1)
        throw Exception(ErrorCodes::BAD_ARGUMENTS,
            "The 'key' should consist of a single attribute for a polygon dictionary");
    IPolygonDictionary::InputType input_type;
    IPolygonDictionary::PointType point_type;
    const auto key_type = (*dict_struct.key)[0].type;
    const auto f64 = std::make_shared<DataTypeFloat64>();
    const auto multi_polygon_array = DataTypeArray(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(f64))));
    const auto multi_polygon_tuple = DataTypeArray(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(std::make_shared<DataTypeTuple>(std::vector<DataTypePtr>{f64, f64}))));