Add a test for NetworkIdentity.getMetered() am: eaca5b1982 am: 1d79f3dd99 am: 27282130c6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1779526

Change-Id: I4267e508a39ceadf09f13e45d6a568dc1bac4600