ethernet: stop using EthernetManager shims am: 81b4b38067

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/18728709

Change-Id: Iffecb3880e9035970ed15c0466b9720ef1bc7ac0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>