Fix the bug on converting new NUD failure metrics to legacy one.

The legacy NUD failure metrics doesn't record provisioning failures due
to multicast resolicits finding that the MAC address has changed, per
current code implemenation, this event will map to NUD_FAILED_ORGANIC,
it's incorrect apparently. Fix this by converting the legacy constants
to NudEventType in strict one-to-one correspondence.

Bug: 162944199
Test: atest NetworkStackTests
Change-Id: I3d8baf4e75a0fb5ff3af87b37cd75d53980e42c2