[automerger skipped] Add CTS for registerNetworkOffer am: cdb727ed50 -s ours

am skip reason: Merged-In Ic3ab3c487d8a9b5a9508b59f83ae35672307b933 with SHA-1 f20360649f is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/14730721

Change-Id: I328eecc56b928b84d259e66ca380163ad6b17214