Shulker box breaking animation is more intense on the bottom half

Relates to MC-265667 and MC-268537. Discovered while testing MC-276756.

The bug

The cracking animation for shulker boxes is more intense on the bottom half of each side of the block than the top half.

How to fix

It may be advisable to have shulker boxes in their closed state be a simple six-sided cube like most other blocks, with dedicated new side, top and bottom texture graphics.