Front Ports count is not updated when removing rear ports.

[Chiniquy]

NetBox version

v3.6.5

Python version

3.8

Steps to Reproduce

Create a device (preferably of a device type without any front or rear ports).
On this device, create a rear port with name "test" and type "Other", with 2 positions.
Create 2 frontports by using "test [1-2]" as name, with type "Other", and select the 2 positions of the newly created rear port.
Now remove the rear port that you created.
On the device view you will now see a "2" on the Front port tab, but there will be no Front Ports inside the tab.

Expected Behavior

If the Front Ports are deleted, then the "2" on the Front Port tab should not be there, and the tab should not be visible.

Observed Behavior

The Front Port tab shows the number "2", indicating the existance of 2 Front Ports. However, when clicking on the Front Port tab, no Front Ports are visible.

[jeremystretch]

It seems that the cascading deletion triggered by removing the rear port is not detected by the tracking logic.

[jeremystretch]

I believe this is the same root problem covered by #14081, so I'm going to close this out as a duplicate (even though its focus is on a different symptom). Happy to reopen it if we see that the fix for #14081 does not resolve this.