```
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
createDecimalWrapper(const DataTypePtr & from_type, const ToDataType * to_type) const
    {
        TypeIndex type_index = from_type->getTypeId();
        UInt32 scale = to_type->getScale();
        WhichDataType which(type_index);
        bool ok = which.isNativeInt() || which.isNativeUInt() || which.isDecimal() || which.isFloat() || which.isDateOrDateTime()
            || which.isStringOrFixedString();
        if (!ok)
        {
            if (cast_type == CastType::accurateOrNull)
                return createToNullableColumnWrapper();
            else
                throw Exception{"Conversion from " + from_type->getName() + " to " + to_type->getName() + " is not supported",
                    ErrorCodes::CANNOT_CONVERT_TYPE};
        }
        auto wrapper_cast_type = cast_type;
        return [wrapper_cast_type, type_index, scale, to_type]
            (ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const ColumnNullable *column_nullable, size_t input_rows_count)
        {
            ColumnPtr result_column;
            auto res = callOnIndexAndDataType<ToDataType>(type_index, [&](const auto & types) -> bool {