Mindclaw Shaman should not allow casting Fuse cards

Fuse only works from *your* hand, not your opponent's hand. You should be able to cast either half of a Fuse card but not both halves fused together.

There's also a test for Mindclaw Shaman that tests if you can cast with Fuse. This should not be possible so test needs to be removed or changed to expect a failure (not sure if this is a thing the test framework supports.)

https://magicjudge.tumblr.com/post/144389585306/does-mindclaw-shaman-allow-you-to-cast-both-halves

> Sadly not.
>
> You can only ever cast both halves of a split card with Fuse when you’re casting it from YOUR hand. Casting it from another player’s hand is just like casting it from anywhere that’s not your hand: You can only cast one half of it.