send out IPv6 DAD packets when starting up clatd for the clat v6 address am: f6ec94ea69

Original change: https://android-review.googlesource.com/c/platform/external/android-clat/+/2153053

Change-Id: I3d46b08d718c34076af4a591130b7ee47f1f096d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>