```
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
{
        FunctionPtr function = FunctionToString::create();
        return createFunctionAdaptor(function, from_type);
    }
    WrapperType createFixedStringWrapper(const DataTypePtr & from_type, const size_t N) const
    {
        if (!isStringOrFixedString(from_type))
            throw Exception{"CAST AS FixedString is only implemented for types String and FixedString", ErrorCodes::NOT_IMPLEMENTED};
        bool exception_mode_null = cast_type == CastType::accurateOrNull;
        return [exception_mode_null, N] (ColumnsWithTypeAndName & arguments, const DataTypePtr &, const ColumnNullable *, size_t )
        {
            if (exception_mode_null)
                return FunctionToFixedString::executeForN<ConvertToFixedStringExceptionMode::Null>(arguments, N);
            else
                return FunctionToFixedString::executeForN<ConvertToFixedStringExceptionMode::Throw>(arguments, N);
        };
    }
    template <typename ToDataType>
    std::enable_if_t<IsDataTypeDecimal<ToDataType>, WrapperType>