Merge changes from topics "cherrypicker-L37800000954756398:N06400001268122372", "cherrypicker-L61200000954646707:N00900001267167505", "cherrypicker-L64000000954631044:N08200001267145803" into tm-dev

* changes:
  Temporarily ignore ethernet tests until prebuilts are updated
  Add CTS tests for EthernetNetworkProvider changes
  Move EthernetNetworkFactory to using the NetworkProvider API
  Add NetworkOfferCallback to NetworkInterfaceState
  Change NetworkInterfaceState to hold NetworkProvider instance
  Improve waiting for interface added or removed
  Always wait for interface to be up in EthernetManagerTest
  Assume all Ethernet interfaces have an MTU of 1500.