ethernet: remove EthernetManager shims am: f8d403cb4a am: 0801cc3aed

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/18728987

Change-Id: Icf8e330e9b4ba0d322e7e58de5f1779bbbdadaad
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>