```
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
{
        FunctionArgumentDescriptors mandatory_args = {{"Value", nullptr, nullptr, nullptr}};
        FunctionArgumentDescriptors optional_args;
        if constexpr (to_decimal)
        {
            mandatory_args.push_back({"scale", &isNativeInteger, &isColumnConst, "const Integer"});
        }
        if (!to_decimal && isDateTime64<Name, ToDataType>(arguments))
        {
            mandatory_args.push_back({"scale", &isNativeInteger, &isColumnConst, "const Integer"});
        }
        
        if ((std::is_same_v<Name, NameToString> && !arguments.empty() && (isDateTime64(arguments[0].type) || isDateTime(arguments[0].type)))
            
            || std::is_same_v<Name, NameToUnixTimestamp>
            
            || std::is_same_v<ToDataType, DataTypeDate> 
            
            || std::is_same_v<ToDataType, DataTypeDateTime>
            
            || std::is_same_v<ToDataType, DataTypeDateTime64>)
        {
            optional_args.push_back({"timezone", &isString, &isColumnConst, "const String"});
        }
        validateFunctionArgumentTypes(*this, arguments, mandatory_args, optional_args);
        if constexpr (std::is_same_v<ToDataType, DataTypeInterval>)