We only track revisions for some notification types, others still
reference usernames, but don't check for suppression status. If no
revision is available, use User::isHidden() to check whether
EchoEvent::getAgent() has been hidden.
Bug: T110553
Change-Id: I31e635e365bbb0f6c6ac63be2bdb07e5e2d67c96
Rather than making each notification type opt-in to using the job queue,
make them opt-out by setting an 'immediate' => true flag.
Configure the 'edit-user-talk' notification type to be immediate since
it should not lag behind the orange bar indicator.
Change-Id: I707bc01a97082887c3f1c353d45cdf1c1eaeff04