BUG: IDX Sync issue with Re-Listed properties

[sfgarza]

Description

In the event that a property is re-listed (same address, but new MLS ID) IMPress Listing's IDX sync feature will import the new listing and will continue to display the old one as active, effectively creating the appearance of a duplicate listing.

How to reproduce the issue

1. Set up a WordPress install with both this plugin and the idxbroker/wordpress-plugin aka IMPress for IDX Broker
2. In the WordPress admin go to IMPress -> Initial Settings and enter a valid IDX Broker API key.
3. Import and sync listings from IDXBroker into WordPress by going to Listings -> Import IDX Listings.
4. Re-List a property that is actively synced in WordPress with the MLS, then wait 24-48 hours for the changes to sync with IDX Broker and then in WordPress.

Expected Outcome

The properties that are synced in WordPress reflect exactly what appears in the IDX Broker Dashboard & the MLS. So if a property is re-listed, the original should be removed and no longer displayed as active.

Actual Outcome

The re-listed property is properly imported and displayed in IDX Broker, but in WordPress the old listing displays as active & the new one is imported. Creating the appearance that the same property is listed twice with different details. At this point to correct the issue the old listing needs to be identified, moved to trash, & then permanently deleted since it can no longer be deleted on the Import IDX Listing page

Versions

WordPress Version: 5.2.1
PHP Version: 7.2
IMPress Listings Version: 2.3.3
IMPress for IDX Broker: 2.5.10