Fix copper golems not able to open barrels

[madebytwentyfive]

The issue here was that isBarrelBlocked and also isShulkerBlocked were not handled correctly.

What I mean, if level.purpurConfig.copperGolemCanOpenBarrel is true, here it incorrectly means the barrel is blocked.

So adding ! to both of these mean if level.purpurConfig.copperGolemCanOpenBarrel is true, then isBarrelBlocked is false, so the golem can open it.

(Same with shulker boxes, even though they also worked before, just because !canOpen is mostly false, so if we can make that true, they won't work either)

This is pretty well tested and it works fine as always.

Fixes #1730