Bug : AR Reminder 'Year' selection Logic

**Description**
The AR reminder job decides which reminders to send using only last_year_reminder_year and ignores last_ar_year. When a business disables reminders via the send AR indicator toggle and later re-enables them, the job would likely resume from the stale reminder year. Example: last_year_reminder_year = 2023 but last_ar_year = 2025 may wrongly triggers reminders for 2024 and 2025.

**Impact**
Businesses that re-enable reminders get incorrect catch-up emails for already-filed years.

**Resolution**
Update the job to use max(last_year_reminder_year, last_ar_year).

**Steps to Test once Fixed**

- Identify/create a business with last_year_reminder_year = 2023, last_ar_year = 2025, send_AR_indicator = false.
- Toggle the AR reminder indicator to true.
- Run the reminder job.
- It should only send reminder for the current year (in this example 2026)