Add methods for updating ingressDiscardRule bpf map to BpfNetMaps am: b01647922d

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/28712473

Change-Id: Idf060b234924379e27f12cd7cd3969b600817c30
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>