The birch tree in the `campsite_old_growth_birch_forest_4` abandoned camp structure never generates

26.3 Snapshot 6 added a fourth campsite variant to each abandoned camp biome pool. The new
Old Growth Birch Forest variant, campsite_old_growth_birch_forest_4, has four tree jigsaw
blocks, but one of them is oriented sideways instead of upwards and therefore can never attach
to the tree it points at. That corner always ends up as a bare dirt block instead of a birch.

Steps to Reproduce

1. Create a Survival world in 26.3 Snapshot 6.

2. Find abandoned camps in an Old Growth Birch Forest biome and keep looking until the camp
   uses variant 4. It is recognisable by its 14x14 footprint — variants 1 and 3 are 10x10 and
   variant 2 is 11x11 — and by having four tree spots rather than one or two. The campsite
   pool has 49 equally weighted entries, so this is roughly a 1-in-49 roll per camp.

3. Look at the four tree spots.

Observed Results

Three super birch trees generate. The fourth spot, at template-local coordinates [12, 0, 11],
is always bare dirt, on every seed and at every rotation.

Expected Results

All four spots generate a super birch, like the three that work.

Cause

The four tree jigsaw blocks in campsite_old_growth_birch_forest_4.nbt all point at the pool
minecraft:abandoned_camp/trees/super_birch_bees, but their orientations differ:

[3, 0, 3] up_west -> works
[3, 0, 10] up_north -> works
[10, 0, 2] up_south -> works
[12, 0, 11] north_up -> never attaches

That pool contains a single minecraft:feature_pool_element.
FeaturePoolElement#getShuffledJigsawBlocks ignores its rotation argument and always produces a
target jigsaw whose front face is DOWN. JigsawBlock#canAttach requires
sourceFront == targetFront.getOpposite(), i.e. the source jigsaw must face UP. The orientation
north_up has a front face of NORTH, and JigsawBlock#rotate only applies the Y-axis rotation, so
NORTH can become EAST, SOUTH or WEST but never UP. The connection is therefore impossible in
all four rotations, and the jigsaw block is replaced by its final_state, minecraft:dirt.

The three working siblings in the same structure all use up_* orientations, and this is the
only jigsaw block in the game that points at a feature-only pool without facing upwards.