Add costly interface rules to make forwarding in both directions

Test: as follows
    - built
    - flashed
    - booted
    - runtest -x system/netd/tests/netd_integration_test.cpp passes
    - runtest -x system/netd/server/netd_unit_test.cpp passes
Bug: 65654957

Change-Id: I62dbe387aaeecb362b2bc69de8f9ce66f163d929