Notifies placed on the first frame of a montage using root motion don't fire

This is a regression in 5.8 caused by 47265321. It's because we now perform the montage update and dispatch the queued notifies via CharacterMovementComponent::TickCharacterPose.  But that all happens before the graph has updated.  So FAnimInstanceProxy::IsSlotNodeRelevantForNotifies fails for the notify that is gathered from the montage on the first frame, because the slot hasn't updated.  Then later in the frame, we do the regular graph update which calls FAnimInstanceProxy::UpdateSlotNodeWeight and makes the slot node relevant, since InMontageLocalWeight is now 1.

Taken from the linked EPS (repros ~50%-75%):

1. Create a project from template: Third Person (C++ version).
2. Open Lvl_ThirdPerson, and set its game mode override to BP_PlatformingGameMode.
3. Open animation sequence MM_Dash, and place an animation notify* at frame zero. *Tested with both a custom BP anim notify that prints a string, and 'Play Niagara Particle Effect' anim notify. Any kind should do, in theory.
4. Start PIE session (net mode: standalone).
5. Execute the character's dash.
6. Observe that the animation notify that we added in step 3 has not been triggered.