[MKM] Implement Call a Surprise Witness

[Cguy7777]

No description provided.

[JayDi85]

Not related to PR: AddCreatureTypeAdditionEffect must be renamed to AddCreatureTypeAdditionTargetEffect cause it uses target.

[xenohedron]

I'm pretty sure this is subtly bugged. Although a straightforward reading of the card text implies that it becomes a Spirit after it enters, rulings on similar effects indicate that it should enter as a Spirit.

Notes and Rules Information for Chainer, Dementia Master:

The creature put onto the battlefield by Chainer’s activated ability is black only, not black in addition to its other colors. It is, however, a Nightmare in addition to its other creature types. As it enters the battlefield, it is already a black Nightmare (and perhaps some other creature types); it doesn’t enter and then become a black Nightmare. (2022-12-08)

I don't mind merging as is anyway, I have a pending rework related to #11168 (a more serious bug) and can include adjustments to this card as part of that.