neigh, test: Also retry upon temporary NUD_FAILED state
neigh, test: Also retry upon temporary NUD_FAILED state

Wasn't able to reproduce the flake even after running the test overnight.
The only explanation I'd have is that there is a small/rare flake due to
a temporary NUD_FAILED state where we won't retry again.

Closes: #18004
Signed-off-by: Daniel Borkmann <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@iogearbox.net>

michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium