Phobos 2.8.0 causes `Akka.Actor.Terminated` messages to be logged from Sharding infrastructure

[Aaronontheweb]

A fun side-effect from some of the noise control improvements that we made in Phobos 2.8.0 - we think that this might be caused by the way we changed how filtering works when being combined with PropagateSettingsToChildren: #85

[Aaronontheweb]

It looks like we've always logged Akka.Actor.Terminated when one is emitted - I think we can probably trim this with a rule though: only trace it if it's part of another trace.