Deprecate 'core.inSample' and introduce 'core.pageviewInSample'

* Offers a clear migration path to 'core.pageviewInSample' for pageview sampling.

Bug: T348776
Bug: T348777
Depends-On: Ib0e1a7fb5ec7023ba82a38f6cc65a692451dd799
Depends-On: I02f9f31ab873144d92b9c97de6bc471cd44fb44d
Change-Id: I58691326282caa4e4a1c934b094172b43ae4eb27
3 files changed