```
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
auto nullable_column_wrapper = FunctionCast::createToNullableColumnWrapper();
                    return nullable_column_wrapper(arguments, result_type, column_nullable, input_rows_count);
                }
                else
                    throw Exception{"Conversion from " + std::string(getTypeName(type_index)) + " to " + to_type->getName() + " is not supported",
                        ErrorCodes::CANNOT_CONVERT_TYPE};
            }
            return result_column;
        };
    }
    WrapperType createAggregateFunctionWrapper(const DataTypePtr & from_type_untyped, const DataTypeAggregateFunction * to_type) const
    {
        
        if (checkAndGetDataType<DataTypeString>(from_type_untyped.get()))
        {
            return [] (ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const ColumnNullable *, size_t )
            {
                return ConvertImplGenericFromString::execute(arguments, result_type);
            };
        }
        else
        {
            if (cast_type == CastType::accurateOrNull)
                return createToNullableColumnWrapper();
            else
                throw Exception{"Conversion from " + from_type_untyped->getName() + " to " + to_type->getName() +
                    " is not supported", ErrorCodes::CANNOT_CONVERT_TYPE};
        }
    }
    WrapperType createArrayWrapper(const DataTypePtr & from_type_untyped, const DataTypeArray * to_type) const