```
SELECT
    CAST(([2, 1, 1023], ['', '']), 'Map(UInt8, String)') AS map,
    map[10]
```

Triggers `Assertion 'n < size()' failed` in `DB::ColumnString::operator[](unsigned long)`
https://clickhouse-test-reports.s3.yandex.net/18481/64c4ade5b0e0c9a13d6c2475431daf431fc97554/fuzzer/fuzzer.log

Introduced here: #17829
First found here: #18481
{
    const auto * arg_type = named_column.type.get();
    bool ok = checkAndGetDataType<DataTypeUInt64>(arg_type)
        || checkAndGetDataType<DataTypeUInt32>(arg_type)
        || checkAndGetDataType<DataTypeUInt16>(arg_type)
        || checkAndGetDataType<DataTypeUInt8>(arg_type);
    if (!ok)
        throw Exception("Illegal type of toDecimal() scale " + named_column.type->getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    Field field;
    named_column.column->get(0, field);
    return field.get<UInt32>();
}
struct NameToUnixTimestamp { static constexpr auto name = "toUnixTimestamp"; };
struct AccurateConvertStrategyAdditions
{
    UInt32 scale { 0 };
};
struct AccurateOrNullConvertStrategyAdditions
{
    UInt32 scale { 0 };
};
struct ConvertDefaultBehaviorTag {};
struct ConvertReturnNullOnErrorTag {};