Calendar doesn't display the `startDate` as first month

[tcpstrh]

Describe the bug
The calendar doesn't display the startDate as first month if monthsShown={2} and selectsRange is set.

To Reproduce
Steps to reproduce the behavior:

Example:

const SelectRangeIssueWith2Months = () => {
  const [startDate, setStartDate] = useState<Date | null>(new Date());
  const [endDate, setEndDate] = useState<Date | null>(null);

  const onChange = (dates: [Date | null, Date | null]) => {
    const [start, end] = dates;
    setStartDate(start);
    setEndDate(end);
  };

  return (
    <DatePicker
      selected={startDate}
      onChange={onChange}
      startDate={startDate}
      endDate={endDate}
      selectsRange
      monthsShown={2}
    />
  );
};

render(SelectRangeIssueWith2Months);

1. Go to input field and select end date
2. Click outside
3. Click into input field

Expected behavior
The calendar display the startDate as first month.

Screenshots
The calendar display the startDate in second month as if showPreviousMonths would be set.

Desktop:

• OS: MacOS
• Browser: chrome
• Version 1.4.1
• react-datepicker version: 8.7.0

Additional context
As a workaround the issue can be fixed by setting the focusSelectedMonth prop. But this introduces another behaviour of the calendar component - selected month is focused (directly set as first month) during user input.

[tcpstrh]

Seems to be related to #5916