Fix CraftWorld#isChunkGenerated

The upstream implementation is returning true for non-full chunks.

This fix is not ideal since the new chunk system doesn't have a region file/chunk status patch. May want to be revisited before a non-experimental release.

patches/server/1027-Fix-CraftWorld-isChunkGenerated.patch

@@ -0,0 +1,46 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
+Date: Tue, 18 Jun 2024 12:43:06 -0700
+Subject: [PATCH] Fix CraftWorld#isChunkGenerated
+
+The upstream implementation is returning true for non-full chunks.
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+index fe9e8d1d4ae1f7a4e8f4cf5688004fc969422b3c..b466a1edaa6c1123dedda8376eabc3be0a011874 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+@@ -367,11 +367,30 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+ 
+     @Override
+     public boolean isChunkGenerated(int x, int z) {
+-        try {
+-            return this.isChunkLoaded(x, z) || this.world.getChunkSource().chunkMap.read(new ChunkPos(x, z)).get().isPresent();
+-        } catch (InterruptedException | ExecutionException ex) {
+-            throw new RuntimeException(ex);
++        // Paper start - Fix this method
++        if (!Bukkit.isPrimaryThread()) {
++            return java.util.concurrent.CompletableFuture.supplyAsync(() -> {
++                return CraftWorld.this.isChunkGenerated(x, z);
++            }, world.getChunkSource().mainThreadProcessor).join();
++        }
++        ChunkAccess chunk = world.getChunkSource().getChunkAtImmediately(x, z);
++        if (chunk == null) {
++            chunk = world.getChunkSource().chunkMap.getUnloadingChunkHolder(x, z).getLatestChunk();
++        }
++        if (chunk != null) {
++            return chunk instanceof ImposterProtoChunk || chunk instanceof net.minecraft.world.level.chunk.LevelChunk;
+         }
++        final java.util.concurrent.CompletableFuture<ChunkAccess> future = new java.util.concurrent.CompletableFuture<>();
++        ca.spottedleaf.moonrise.patches.chunk_system.ChunkSystem.scheduleChunkLoad(
++            this.world, x, z, false, ChunkStatus.EMPTY, false, ca.spottedleaf.concurrentutil.executor.standard.PrioritisedExecutor.Priority.NORMAL, future::complete
++        );
++        return future.thenApply(c -> {
++            if (c != null) {
++                return c.getPersistedStatus() == ChunkStatus.FULL;
++            }
++            return false;
++        }).join();
++        // Paper end - Fix this method
+     }
+ 
+     @Override