ApfFilter: refactor/simplify ipv4 if mMulticastFilter am: 5ecede272b

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

Change-Id: I8a53b8e017dd8a45f157511ac4e18424d13ae60a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>