Hello!

I've started to use `DateTime64` recently and faced the next issue with `toDate()`/`toDate32()` functions.

This query works fine:
```sql
SELECT toDate('2022-07-26 00:00:00')

Query id: bf64d8a8-018d-4b3e-ae24-f92600a1fa15

┌─toDate('2022-07-26 00:00:00')─┐
│                    2022-07-26 │
└───────────────────────────────┘

1 rows in set. Elapsed: 0.003 sec.
```

But when the string representation of the timestamp has the milliseconds fraction the function does not work:
```sql
SELECT toDate('2022-07-26 00:00:00.000')

Query id: 8b42473a-0ceb-4892-b0e7-6f73f583d4b4


0 rows in set. Elapsed: 0.006 sec.

Received exception from server (version 22.3.8):
Code: 6. DB::Exception: Received from s:9000. DB::Exception: Cannot parse string '2022-07-26 00:00:00.000' as Date: syntax error at position 10 (parsed just '2022-07-26'): While processing toDate('2022-07-26 00:00:00.000'). (CANNOT_PARSE_TEXT)
```

The `toDate32()` doesn't work in both cases.

Yes, you can say I must change the input or use a workaround like this:
```sql
SELECT toDate(toDateTime64('2022-07-26 00:00:00.000', 3, 'UTC')) AS date
```

But it's not convenient and it'd be great if the mentioned functions will ignore the time part.

P.s. ClickHouse server version: `22.3.8.39`

{
        const auto * from_low_cardinality = typeid_cast<const DataTypeLowCardinality *>(from_type.get());
        const auto * to_low_cardinality = typeid_cast<const DataTypeLowCardinality *>(to_type.get());
        const auto & from_nested = from_low_cardinality ? from_low_cardinality->getDictionaryType() : from_type;
        const auto & to_nested = to_low_cardinality ? to_low_cardinality->getDictionaryType() : to_type;
        if (from_type->onlyNull())
        {
            if (!to_nested->isNullable())
            {
                if (cast_type == CastType::accurateOrNull)
                {
                    return createToNullableColumnWrapper();
                }
                else
                {
                    throw Exception{"Cannot convert NULL to a non-nullable type", ErrorCodes::CANNOT_CONVERT_TYPE};
                }
            }
            return [](ColumnsWithTypeAndName &, const DataTypePtr & result_type, const ColumnNullable *, size_t input_rows_count)
            {
                return result_type->createColumnConstWithDefaultValue(input_rows_count)->convertToFullColumnIfConst();
            };