Shulker box opening detection is faulty.

The opening detection logic for Shulker Boxes is inconsistent when interacting with half-slabs in front of the opening direction.

Reproduction Steps:

(As shown in the attached video)

* Place a Shulker Box.

* Place a top/bottom half-slab directly in front of the box's opening direction.

Actual Results:

* If a top half-slab is placed, the box opens.

* If a bottom half-slab is placed, the box does not open.

Current Logic Analysis:

The current logic checks for the presence of a block specifically on the lower half of the space in front of the opening direction.

Expected Results:

The Shulker Box should open regardless of the slab position, as long as the opening animation does not visually overlap or collide with another solid block.