```
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
{
public:
    using Monotonic = MonotonicityImpl;
    static constexpr auto name = Name::name;
    static constexpr bool to_decimal =
        std::is_same_v<Name, NameToDecimal32> || std::is_same_v<Name, NameToDecimal64>
         || std::is_same_v<Name, NameToDecimal128> || std::is_same_v<Name, NameToDecimal256>;
    static constexpr bool to_datetime64 = std::is_same_v<ToDataType, DataTypeDateTime64>;
    static constexpr bool to_string_or_fixed_string = std::is_same_v<ToDataType, DataTypeFixedString> ||
                                                      std::is_same_v<ToDataType, DataTypeString>;
    static FunctionPtr create(const Context &) { return std::make_shared<FunctionConvert>(); }
    static FunctionPtr create() { return std::make_shared<FunctionConvert>(); }
    String getName() const override
    {
        return name;
    }
    bool isVariadic() const override { return true; }
    size_t getNumberOfArguments() const override { return 0; }
    bool isInjective(const ColumnsWithTypeAndName &) const override { return std::is_same_v<Name, NameToString>; }
    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
    {
        auto getter = [&] (const auto & args) { return getReturnTypeImplRemovedNullable(args); };
        auto res = FunctionOverloadResolverAdaptor::getReturnTypeDefaultImplementationForNulls(arguments, getter);
        to_nullable = res->isNullable();
        checked_return_type = true;
        return res;
    }
    DataTypePtr getReturnTypeImplRemovedNullable(const ColumnsWithTypeAndName & arguments) const