Code that needs to store an actor ID in the database to
represent a UserIdentity, or needs to construct a UserIdentity based on
an actor ID loaded from the database, should use the ActorNormalization
service.
Note: The getActorId() method is removed from the UserIdentity interface,
but all concrete classes continue to support it for now.
UsererIdentityValue::getActorId() is hard deprecated and should
be removed in 1.37. It always returns 0.
User::getActorId() is not deprecated at this point.
Bug: T274179
Depends-On: Id2b3ddf6a2a7cdf90f8936a69148d2cce6fde237
Change-Id: I9925906d11e47efaec3c1f48d5cb3f9896a982c1
