Remove NetworkIdentitySet usage in CTS am: 5711f9e6ae

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/18399677

Change-Id: I35aae0373dbf75b0b1348291ebe9cc3171d84a9c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>