```
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
if (from_is_unsigned == to_is_unsigned)
                return {true, true, true};
            if (!to_is_unsigned)
                return {true, true, true};
            
            if (left_in_first_half == right_in_first_half)
                return {true};
            return {};
        }
        
        if (size_of_from > size_of_to)
        {
            
            if (left.isNull() || right.isNull())
                return {};
            
            if (divideByRangeOfType(left.get<UInt64>()) != divideByRangeOfType(right.get<UInt64>()))
                return {};
            if (to_is_unsigned)
                return {true};
            else
                
                return {(T(left.get<UInt64>()) >= 0) == (T(right.get<UInt64>()) >= 0)};
        }
        __builtin_unreachable();
    }
};
struct ToDateMonotonicity
{
    static bool has() { return true; }