**Describe the unexpected behaviour**
If Null being passed as dictionary key, dictGetOrDefault returns null instead of default value.

**How to reproduce**
Clickhouse version 21.5, 21.1, 20.8

```

CREATE VIEW dict_null_source AS SELECT 1 as key, 1 as val;
CREATE DICTIONARY dict_null (key UInt64, val UInt32) PRIMARY KEY key SOURCE(CLICKHOUSE(host 'localhost' user 'default' table 'dict_null_source' ))LAYOUT(FLAT)LIFETIME(300)


SELECT dictGetOrDefault('default.dict_null', 'val', CAST(NULL, 'Nullable(UInt64)'), 0) AS val

Query id: 79518a8e-b439-4d08-a0b2-85e4b3ef99eb

┌──val─┐
│ ᴺᵁᴸᴸ │
└──────┘
```

**Additional context**
```

SELECT dictGetOrDefault('default.dict_null', 'val', CAST(1, 'UInt64'))

Query id: 71ec76a1-fb61-4641-9145-79c6bfffd490


0 rows in set. Elapsed: 0.001 sec.

Received exception from server (version 21.5.1):
Code: 42. DB::Exception: Received from localhost:9000. DB::Exception: Wrong argument count for function dictGetOrDefault: While processing dictGetOrDefault('default.dict_null', 'val', CAST(1, 'UInt64')).

```

Error message in 21.1 was better:  `Number of arguments for function dictGetOrDefault doesn't match: passed 3, should be 4:`

struct NameDictGetInt16OrDefault { static constexpr auto name = "dictGetInt16OrDefault"; };
struct NameDictGetInt32OrDefault { static constexpr auto name = "dictGetInt32OrDefault"; };
struct NameDictGetInt64OrDefault { static constexpr auto name = "dictGetInt64OrDefault"; };
struct NameDictGetFloat32OrDefault { static constexpr auto name = "dictGetFloat32OrDefault"; };
struct NameDictGetFloat64OrDefault { static constexpr auto name = "dictGetFloat64OrDefault"; };
struct NameDictGetDateOrDefault { static constexpr auto name = "dictGetDateOrDefault"; };
struct NameDictGetDateTimeOrDefault { static constexpr auto name = "dictGetDateTimeOrDefault"; };
struct NameDictGetUUIDOrDefault { static constexpr auto name = "dictGetUUIDOrDefault"; };
struct NameDictGetDecimal32OrDefault { static constexpr auto name = "dictGetDecimal32OrDefault"; };
struct NameDictGetDecimal64OrDefault { static constexpr auto name = "dictGetDecimal64OrDefault"; };
struct NameDictGetDecimal128OrDefault { static constexpr auto name = "dictGetDecimal128OrDefault"; };
struct NameDictGetStringOrDefault { static constexpr auto name = "dictGetStringOrDefault"; };
using FunctionDictGetUInt8OrDefault = FunctionDictGetOrDefault<DataTypeUInt8, NameDictGetUInt8OrDefault>;
using FunctionDictGetUInt16OrDefault = FunctionDictGetOrDefault<DataTypeUInt16, NameDictGetUInt16OrDefault>;
using FunctionDictGetUInt32OrDefault = FunctionDictGetOrDefault<DataTypeUInt32, NameDictGetUInt32OrDefault>;
using FunctionDictGetUInt64OrDefault = FunctionDictGetOrDefault<DataTypeUInt64, NameDictGetUInt64OrDefault>;
using FunctionDictGetInt8OrDefault = FunctionDictGetOrDefault<DataTypeInt8, NameDictGetInt8OrDefault>;
using FunctionDictGetInt16OrDefault = FunctionDictGetOrDefault<DataTypeInt16, NameDictGetInt16OrDefault>;
using FunctionDictGetInt32OrDefault = FunctionDictGetOrDefault<DataTypeInt32, NameDictGetInt32OrDefault>;
using FunctionDictGetInt64OrDefault = FunctionDictGetOrDefault<DataTypeInt64, NameDictGetInt64OrDefault>;
using FunctionDictGetFloat32OrDefault = FunctionDictGetOrDefault<DataTypeFloat32, NameDictGetFloat32OrDefault>;
using FunctionDictGetFloat64OrDefault = FunctionDictGetOrDefault<DataTypeFloat64, NameDictGetFloat64OrDefault>;
using FunctionDictGetDateOrDefault = FunctionDictGetOrDefault<DataTypeDate, NameDictGetDateOrDefault>;
using FunctionDictGetDateTimeOrDefault = FunctionDictGetOrDefault<DataTypeDateTime, NameDictGetDateTimeOrDefault>;
using FunctionDictGetUUIDOrDefault = FunctionDictGetOrDefault<DataTypeUUID, NameDictGetUUIDOrDefault>;
using FunctionDictGetDecimal32OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal32>, NameDictGetDecimal32OrDefault>;
using FunctionDictGetDecimal64OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal64>, NameDictGetDecimal64OrDefault>;
using FunctionDictGetDecimal128OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal128>, NameDictGetDecimal128OrDefault>;
using FunctionDictGetStringOrDefault = FunctionDictGetOrDefault<DataTypeString, NameDictGetStringOrDefault>;
class FunctionDictGetOrNull final : public IFunction