**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 auto * ptr_polygons = typeid_cast<const ColumnArray*>(column.get());
    if (!ptr_polygons)
        throw Exception(ErrorCodes::TYPE_MISMATCH, "Expected a column containing arrays of points");
    offset.ring_offsets.assign(ptr_polygons->getOffsets());
    std::iota(offset.polygon_offsets.begin(), offset.polygon_offsets.end(), 1);
    offset.multi_polygon_offsets.assign(offset.polygon_offsets);
    return ptr_polygons->getDataPtr().get();
}
void handlePointsReprByArrays(const IColumn * column, Data & data, Offset & offset)
{
    const auto * ptr_points = typeid_cast<const ColumnArray*>(column);
    const auto * ptr_coord = typeid_cast<const ColumnVector<Float64>*>(&ptr_points->getData());
    if (!ptr_coord)
        throw Exception(ErrorCodes::TYPE_MISMATCH, "Expected coordinates to be of type Float64");
    const auto & offsets = ptr_points->getOffsets();
    IColumn::Offset prev_offset = 0;
    for (size_t i = 0; i < offsets.size(); ++i)
    {
        if (offsets[i] - prev_offset != 2)
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "All points should be two-dimensional");
        prev_offset = offsets[i];
        addNewPoint(ptr_coord->getElement(2 * i), ptr_coord->getElement(2 * i + 1), data, offset);
    }
}
void handlePointsReprByTuples(const IColumn * column, Data & data, Offset & offset)