fix($animate): don't break on anchored animations without duration

If the `from` element of an animation does not actually have an animation
then there will be no animation runner on that element. This is possible
if the element has the `ng-animate-ref` attribute but does not have any
CSS animations or transitions defined.

In this case, it is not necessary to try to update the host of the
non-existent runner.

Fixes #14641
Closes #14645