Until now, these were haphazardly enforce inline in blueprint
implementations. The only thing stopping complete breakage is that
`EndPlacement` wasn't called (too much) from outside the blueprint,
leaving them responsible for their own placement.
By moving this conditional out of the provided paramters to
`EndPlacement`, it allows more flexible usage of that method externally.
Coming in a future PR.
Previously, some judgement results were not reverted
when the source DHO is not alive (e.g. frames skipped in editor).
Now, all results are reverted in the exact reverse order.