ApfFilter: refactor/simplify ipv4 if mMulticastFilter am: 5ecede272b am: 6c6f832fb2 am: 5cedec31e5

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/2857925

Change-Id: I29148237973be0293ae67b4dc000217b6a3d6088
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>