Fix non-null initialisation of context collision shape

Force LazyEntityCollisionContext#getEntity() to delegate

- By delegating when the entity is retrieved, we can correctly catch
  cases where the collision method is inspecting some entity state.

Adjust constant collision shape determination

- Our previous hack did not actually catch every case. For now,
  it will only assume a constant collision shape of EMPTY for
  air blocks.

Fixes https://github.com/PaperMC/Paper/issues/11697

patches/server/Moonrise-optimisation-patches.patch

@@ -18347,11 +18347,17 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +
 +        public CollisionContext getDelegate() {
 +            this.delegated = true;
-+            final Entity entity = this.getEntity();
++            final Entity entity = super.getEntity();
 +            return this.delegate == null ? this.delegate = (entity == null ? CollisionContext.empty() : CollisionContext.of(entity)) : this.delegate;
 +        }
 +
 +        @Override
++        public Entity getEntity() {
++            this.getDelegate();
++            return super.getEntity();
++        }
++
++        @Override
 +        public boolean isDescending() {
 +            return this.getDelegate().isDescending();
 +        }
@@ -31088,9 +31094,9 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +            // Paper start - optimise collisions
 +            if (this.cache != null) {
 +                final VoxelShape collisionShape = this.cache.collisionShape;
-+                try {
-+                    this.constantCollisionShape = this.getCollisionShape(null, null, null);
-+                } catch (final Throwable throwable) {
++                if (this.isAir()) {
++                    this.constantCollisionShape = Shapes.empty();
++                } else {
 +                    this.constantCollisionShape = null;
 +                }
 +                this.occludesFullBlock = ((ca.spottedleaf.moonrise.patches.collisions.shape.CollisionVoxelShape)collisionShape).moonrise$occludesFullBlock();