=act #15186 add missing string interpolators

Thanks @retronym for finding these in the logs!

fixes #15186
=act #15165 should fix out-of-bounds in actor creation
Other than that, also improved failure logging when AIOOB happens in the histogram
Added a test which shows why the updateWithExpectedInterval method
should be preferred too.
+act Add japi.Pair and japi.Predicate for streams

(cherry picked from commit 42ce37bb57884c7051d46a1e80b4a4ba4187adf4)

=act Add @SerialVersionUID to japi.Pair

(cherry picked from commit adb2c9bdc20effc84132daaf37e563fb430bf230)
Merge pull request #15169 from ktoso/fix-15165-actor-cration-histogram-OOB

=act #15165 should fix out-of-bounds in actor creation
Merge pull request #15187 from akka/wip-15186-interpolators-∂π

=act #15186 add missing string interpolators
Merge pull request #15199 from akka/wip-stream-japi-master-patriknw

+act Add japi.Pair and japi.Predicate for streams (for validation)
Changed ClusterSharding.start to return the ActorRef to the shardRegion (#15157)