Enforce structural NetworkAgent constraints am: 78c9a381c9 am: f9d930b816 am: 48718509cc

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2805415

Change-Id: I89a919233b8f44356bf401968690281c7564b28b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>