[Thread] add a test case to validate the default upstream network request am: 89a81a15be

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3206413

Change-Id: I9ef7ced5239884d5c216ad28261a7f1be6270f85
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>