ethernet: delete testListenEthernetStateChange

This test has been broken for a while. It tested:
- adding a listener triggers an interface state changed callback and an
  ethernet state changed callback.
- setEthernetEnabled calls back the correct listeners and removes / adds
  the interface.

Interface state listeners are already well covered in
EthernetManagerTest. I am currently working on adding tests for
setEthernetEnabled (there is partial coverage in setUp and tearDown of
EthernetManagerTest).

Bug: 242671512
Test: atest EthernetTrackerTest
Change-Id: Id1325a9056384444affb5c096cbc19d200ae0c4e
1 file changed