Cable still not tracing when creating frontports after connecting rearport

[PaulR282]

NetBox version

v3.3.8

Python version

3.10

Steps to Reproduce

In addition to #10237. While experimenting I was able to reproduce the problem (in v3.3.8 and v3.4-beta1) and now know why you couldn't reproduce it. My steps to reproduce were wrong.

1. Create 2 devices with interfaces (switches 1 and 2)
2. Create 2 devices with no components (patchpanel 1 and 2)
3. Create a rearport in both patchpanel
4. Create a frontport in patchpanel 1 and map it to the rearport
5. Connect the rearports
6. Connect the only existing frontport to an interface of switch 1
   -> Through looking in the database I found out that now the first trace gets created (i->fp->rp->rp)
7. Create a frontport on patchpanel 2 and map it to the rearport
8. Connect this frontport to an interface of switch 2
   -> Now the Second trace gets created (i->fp->rp->rp->fp->i)

If you do it as I said in #10237, the trace gets created when the frontports are already mapped to the rearport, resulting in 2 complete paths and avoiding this bug.

Expected Behavior

When mapping the second frontport to a rearport the trace should get extended.

Observed Behavior

The first trace keeps link i->fp->rp->rp. This way the trace is only in one direction complete.

[jeremystretch]

Thanks for taking the time to track this down @PaulR282. I believe the root issue is that the incomplete cable path originating from the interface on switch1 is not being extended when the front port on patchpanel2 is created. This should be simple enough to fix by introducing a new signal handler specifically for front ports.