The test actually does not need the ethernet interface to be the
only ethernet interface, as ethernet test interfaces now have
TRANSPORT_TEST|TRANSPORT_ETHERNET, which can be used to differentiate
them in the network request.
Bug: 162469293
Test: atest CtsNetTestCasesLatestSdk:NetworkValidationTest
Change-Id: I84cc8b6b9aaa764705d91ed298655d869c4388a6