Accessing svc.Spec.IPFamilies[0] without a bounds check panics when a
service reaches the controller with an empty IPFamilies field. This can
happen via watch events: the apiserver's defaultOnRead decorator populates
IPFamilies on GET/LIST but not on watch (cachingObject wrapping bypasses
the type assertion).
Restore the inference logic removed in #130101: fall back to ClusterIP
for headful services and pod IP for headless services.
Signed-off-by: Rahul <rahulbabu95@gmail.com>