[RFCLAT#3] Move the tun interface setup from clatd to netd am: 5dafb0e92c am: a518daebcc am: 8a8ae1f8ea

Original change: https://android-review.googlesource.com/c/platform/external/android-clat/+/1903035

Change-Id: I3fa179a47c346ed1690638f70e5a73c7894b6af2