ClusterShardingLeaseSpec: extractShardId should include StartEntity

[octonato]

References #30622

The shard was never coming back to life because of the following exception.

java.lang.IllegalArgumentException
 at akka.cluster.sharding.ClusterShardingLeaseSpec$.$anonfun$extractShardId$1(ClusterShardingLeaseSpec.scala:55)
 at akka.cluster.sharding.ShardRegion.deliverMessage(ShardRegion.scala:1245)
 at akka.cluster.sharding.ShardRegion.deliverStartEntity(ShardRegion.scala:1213)
 at akka.cluster.sharding.ShardRegion$$anonfun$receive$2.applyOrElse(ShardRegion.scala:732) 
 at akka.actor.Actor.aroundReceive(Actor.scala:537) 
 at akka.actor.Actor.aroundReceive$(Actor.scala:535)
 at akka.cluster.sharding.ShardRegion.akka$actor$Timers$$super$aroundReceive(ShardRegion.scala:588) 
 at akka.actor.Timers.aroundReceive(Timers.scala:56)
 at akka.actor.Timers.aroundReceive$(Timers.scala:41)

StartEntity was getting in before the Int sent by the test. Surprising that we never hit that before (or didn't notice).

[patriknw]

LGTM