Skip adding ingress discard rule to legacy VPN am: 5441470a6a

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/28724995

Change-Id: Ib208feb4946e1f51eb2cdd956514b307635e1e43
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>